diff --git a/doc/pub/week39/html/week39-reveal.html b/doc/pub/week39/html/week39-reveal.html
index 3f1786185..e5d488e8f 100644
--- a/doc/pub/week39/html/week39-reveal.html
+++ b/doc/pub/week39/html/week39-reveal.html
@@ -893,7 +893,7 @@ $$
     <span style="color: #8B008B; font-weight: bold">return</span> np.array([<span style="color: #B452CD">2</span>*x[<span style="color: #B452CD">0</span>], <span style="color: #B452CD">6</span>*x[<span style="color: #B452CD">1</span>]])
 
 fig = pt.figure()
-ax = fig.gca(projection=<span style="color: #CD5555">&quot;3d&quot;</span>)
+ax = fig.add_subplot(projection = <span style="color: #CD5555">&#39;3d&#39;</span>)
 
 xmesh, ymesh = np.mgrid[-<span style="color: #B452CD">3</span>:<span style="color: #B452CD">3</span>:<span style="color: #B452CD">50</span>j,-<span style="color: #B452CD">3</span>:<span style="color: #B452CD">3</span>:<span style="color: #B452CD">50</span>j]
 fmesh = f(np.array([xmesh, ymesh]))
diff --git a/doc/pub/week39/html/week39-solarized.html b/doc/pub/week39/html/week39-solarized.html
index ba0233281..40df3a265 100644
--- a/doc/pub/week39/html/week39-solarized.html
+++ b/doc/pub/week39/html/week39-solarized.html
@@ -953,7 +953,7 @@ $$
     <span style="color: #8B008B; font-weight: bold">return</span> np.array([<span style="color: #B452CD">2</span>*x[<span style="color: #B452CD">0</span>], <span style="color: #B452CD">6</span>*x[<span style="color: #B452CD">1</span>]])
 
 fig = pt.figure()
-ax = fig.gca(projection=<span style="color: #CD5555">&quot;3d&quot;</span>)
+ax = fig.add_subplot(projection = <span style="color: #CD5555">&#39;3d&#39;</span>)
 
 xmesh, ymesh = np.mgrid[-<span style="color: #B452CD">3</span>:<span style="color: #B452CD">3</span>:<span style="color: #B452CD">50</span>j,-<span style="color: #B452CD">3</span>:<span style="color: #B452CD">3</span>:<span style="color: #B452CD">50</span>j]
 fmesh = f(np.array([xmesh, ymesh]))
diff --git a/doc/pub/week39/html/week39.html b/doc/pub/week39/html/week39.html
index 59e7126b5..b58c4d8be 100644
--- a/doc/pub/week39/html/week39.html
+++ b/doc/pub/week39/html/week39.html
@@ -1030,7 +1030,7 @@ $$
     <span style="color: #008000; font-weight: bold">return</span> np<span style="color: #666666">.</span>array([<span style="color: #666666">2*</span>x[<span style="color: #666666">0</span>], <span style="color: #666666">6*</span>x[<span style="color: #666666">1</span>]])
 
 fig <span style="color: #666666">=</span> pt<span style="color: #666666">.</span>figure()
-ax <span style="color: #666666">=</span> fig<span style="color: #666666">.</span>gca(projection<span style="color: #666666">=</span><span style="color: #BA2121">&quot;3d&quot;</span>)
+ax <span style="color: #666666">=</span> fig<span style="color: #666666">.</span>add_subplot(projection <span style="color: #666666">=</span> <span style="color: #BA2121">&#39;3d&#39;</span>)
 
 xmesh, ymesh <span style="color: #666666">=</span> np<span style="color: #666666">.</span>mgrid[<span style="color: #666666">-3</span>:<span style="color: #666666">3</span>:<span style="color: #666666">50</span>j,<span style="color: #666666">-3</span>:<span style="color: #666666">3</span>:<span style="color: #666666">50</span>j]
 fmesh <span style="color: #666666">=</span> f(np<span style="color: #666666">.</span>array([xmesh, ymesh]))
diff --git a/doc/pub/week39/ipynb/ipynb-week39-src.tar.gz b/doc/pub/week39/ipynb/ipynb-week39-src.tar.gz
index da74dbffd..9c6e9a4d6 100644
Binary files a/doc/pub/week39/ipynb/ipynb-week39-src.tar.gz and b/doc/pub/week39/ipynb/ipynb-week39-src.tar.gz differ
diff --git a/doc/pub/week39/ipynb/week39.ipynb b/doc/pub/week39/ipynb/week39.ipynb
index 7c861c310..874690134 100644
--- a/doc/pub/week39/ipynb/week39.ipynb
+++ b/doc/pub/week39/ipynb/week39.ipynb
@@ -2,7 +2,7 @@
  "cells": [
   {
    "cell_type": "markdown",
-   "id": "918e6088",
+   "id": "a777059d",
    "metadata": {
     "editable": true
    },
@@ -14,7 +14,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "f6bdc2db",
+   "id": "46de5112",
    "metadata": {
     "editable": true
    },
@@ -27,7 +27,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "0fd73813",
+   "id": "d1a193dd",
    "metadata": {
     "editable": true
    },
@@ -37,7 +37,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "4659a144",
+   "id": "9b00826d",
    "metadata": {
     "editable": true
    },
@@ -67,7 +67,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "fc1f68ca",
+   "id": "31cff1ed",
    "metadata": {
     "editable": true
    },
@@ -94,7 +94,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "15869b1d",
+   "id": "e5b080b4",
    "metadata": {
     "editable": true
    },
@@ -115,7 +115,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "cfaf747a",
+   "id": "7961520d",
    "metadata": {
     "editable": true
    },
@@ -132,7 +132,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "e2850b85",
+   "id": "271b3e55",
    "metadata": {
     "editable": true
    },
@@ -147,7 +147,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "a73f7a09",
+   "id": "b95e7beb",
    "metadata": {
     "editable": true
    },
@@ -157,7 +157,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "eee9af50",
+   "id": "2f95cd51",
    "metadata": {
     "editable": true
    },
@@ -173,7 +173,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "d8a40aeb",
+   "id": "6808dbc0",
    "metadata": {
     "editable": true
    },
@@ -185,7 +185,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "7d24b6f4",
+   "id": "3587718c",
    "metadata": {
     "editable": true
    },
@@ -196,7 +196,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "da0033f7",
+   "id": "fdd1ac66",
    "metadata": {
     "editable": true
    },
@@ -208,7 +208,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "eff96c8f",
+   "id": "6730fa45",
    "metadata": {
     "editable": true
    },
@@ -218,7 +218,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "bbf59e32",
+   "id": "9cec7a4a",
    "metadata": {
     "editable": true
    },
@@ -232,7 +232,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "67e16976",
+   "id": "10943d88",
    "metadata": {
     "editable": true
    },
@@ -244,7 +244,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "374d66a6",
+   "id": "7a13c3ad",
    "metadata": {
     "editable": true
    },
@@ -254,7 +254,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "ed30dea2",
+   "id": "2ac20e20",
    "metadata": {
     "editable": true
    },
@@ -266,7 +266,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "f098e947",
+   "id": "64b91f34",
    "metadata": {
     "editable": true
    },
@@ -278,7 +278,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "741d9a60",
+   "id": "4140ce15",
    "metadata": {
     "editable": true
    },
@@ -298,7 +298,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "dff616d1",
+   "id": "0fbbfbd1",
    "metadata": {
     "editable": true
    },
@@ -314,7 +314,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "5d37722e",
+   "id": "84503a94",
    "metadata": {
     "editable": true
    },
@@ -330,7 +330,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "6706784b",
+   "id": "b7747b50",
    "metadata": {
     "editable": true
    },
@@ -341,7 +341,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "3708fdef",
+   "id": "fabc0335",
    "metadata": {
     "editable": true
    },
@@ -353,7 +353,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "3f607de4",
+   "id": "53f11b98",
    "metadata": {
     "editable": true
    },
@@ -363,7 +363,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "bdb0ec30",
+   "id": "2eb35f3b",
    "metadata": {
     "editable": true
    },
@@ -375,7 +375,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "e941f0f2",
+   "id": "efec77fc",
    "metadata": {
     "editable": true
    },
@@ -385,7 +385,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "2a7d9a7f",
+   "id": "21126b1b",
    "metadata": {
     "editable": true
    },
@@ -397,7 +397,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "9c9bfa29",
+   "id": "fdc972f4",
    "metadata": {
     "editable": true
    },
@@ -419,7 +419,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "e6fecd57",
+   "id": "ea541470",
    "metadata": {
     "editable": true
    },
@@ -432,7 +432,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "250ae3be",
+   "id": "8aab454c",
    "metadata": {
     "editable": true
    },
@@ -445,7 +445,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "13f76c19",
+   "id": "dddbac54",
    "metadata": {
     "editable": true
    },
@@ -455,7 +455,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "7c8dabb7",
+   "id": "dbd9d9f5",
    "metadata": {
     "editable": true
    },
@@ -473,7 +473,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "74eaf63d",
+   "id": "1c0a9093",
    "metadata": {
     "editable": true
    },
@@ -483,7 +483,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "4a58d03d",
+   "id": "7605435e",
    "metadata": {
     "editable": true
    },
@@ -498,7 +498,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "ad5a8242",
+   "id": "55378b51",
    "metadata": {
     "editable": true
    },
@@ -508,7 +508,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "2d1a3ad3",
+   "id": "a561f6fe",
    "metadata": {
     "editable": true
    },
@@ -522,7 +522,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "3f664794",
+   "id": "c72184c0",
    "metadata": {
     "editable": true
    },
@@ -532,7 +532,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "2605bf0e",
+   "id": "1bd1036d",
    "metadata": {
     "editable": true
    },
@@ -546,7 +546,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "01f6d82b",
+   "id": "507767b7",
    "metadata": {
     "editable": true
    },
@@ -561,7 +561,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "92fbc947",
+   "id": "910e542b",
    "metadata": {
     "editable": true
    },
@@ -578,7 +578,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "4456e346",
+   "id": "f58db334",
    "metadata": {
     "editable": true
    },
@@ -590,7 +590,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "98859a0d",
+   "id": "a0d4a17a",
    "metadata": {
     "editable": true
    },
@@ -604,7 +604,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "3249ff28",
+   "id": "ec6c63eb",
    "metadata": {
     "editable": true
    },
@@ -619,7 +619,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "bc3514ae",
+   "id": "c7a3d764",
    "metadata": {
     "editable": true
    },
@@ -631,7 +631,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "7dc046a6",
+   "id": "7e0fc177",
    "metadata": {
     "editable": true
    },
@@ -642,7 +642,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "0b885ad4",
+   "id": "22bdeee8",
    "metadata": {
     "editable": true
    },
@@ -670,7 +670,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "800ed299",
+   "id": "42e70771",
    "metadata": {
     "editable": true
    },
@@ -692,7 +692,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "bfd9b49f",
+   "id": "1feefc33",
    "metadata": {
     "editable": true
    },
@@ -714,7 +714,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "7cc0574a",
+   "id": "7bab34f0",
    "metadata": {
     "editable": true
    },
@@ -735,7 +735,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "a4a7e0d2",
+   "id": "d343afa6",
    "metadata": {
     "editable": true
    },
@@ -774,7 +774,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "4ac4f3dd",
+   "id": "5443319d",
    "metadata": {
     "editable": true
    },
@@ -802,7 +802,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "e2c3e2b8",
+   "id": "80986952",
    "metadata": {
     "editable": true
    },
@@ -832,7 +832,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "3cbf5677",
+   "id": "c07bbe7c",
    "metadata": {
     "editable": true
    },
@@ -852,7 +852,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "8b46198f",
+   "id": "bcbd1b3b",
    "metadata": {
     "editable": true
    },
@@ -864,7 +864,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "87174dcb",
+   "id": "1f185d0d",
    "metadata": {
     "editable": true
    },
@@ -874,7 +874,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "5af2eb1c",
+   "id": "98da82e3",
    "metadata": {
     "editable": true
    },
@@ -886,7 +886,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "977cfa69",
+   "id": "ac8a468b",
    "metadata": {
     "editable": true
    },
@@ -898,7 +898,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "68fd5ea0",
+   "id": "2b84de67",
    "metadata": {
     "editable": true
    },
@@ -910,7 +910,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "4e2bae9e",
+   "id": "a3c957bf",
    "metadata": {
     "editable": true
    },
@@ -922,7 +922,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "bcbbad7f",
+   "id": "25fa3a34",
    "metadata": {
     "editable": true
    },
@@ -933,7 +933,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "67d8e3f3",
+   "id": "e62898a8",
    "metadata": {
     "editable": true
    },
@@ -946,7 +946,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "7519f74e",
+   "id": "d9ddaae6",
    "metadata": {
     "editable": true
    },
@@ -958,7 +958,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "f0b6000e",
+   "id": "6631af76",
    "metadata": {
     "editable": true
    },
@@ -968,7 +968,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "0a5e83d1",
+   "id": "3e6fc2e7",
    "metadata": {
     "editable": true
    },
@@ -980,7 +980,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "fff9b0be",
+   "id": "cb06c395",
    "metadata": {
     "editable": true
    },
@@ -990,7 +990,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "2be695a7",
+   "id": "a9142100",
    "metadata": {
     "editable": true
    },
@@ -1001,7 +1001,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "1bcf856f",
+   "id": "7b2840aa",
    "metadata": {
     "editable": true
    },
@@ -1013,7 +1013,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "6dd2c43f",
+   "id": "e6841448",
    "metadata": {
     "editable": true
    },
@@ -1025,7 +1025,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "a4d7a932",
+   "id": "1853852f",
    "metadata": {
     "editable": true
    },
@@ -1037,7 +1037,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "20db9bfe",
+   "id": "ffc5e08b",
    "metadata": {
     "editable": true
    },
@@ -1048,7 +1048,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "cde76790",
+   "id": "6831a3e3",
    "metadata": {
     "editable": true
    },
@@ -1059,7 +1059,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "c1ba27a3",
+   "id": "8f68f769",
    "metadata": {
     "editable": true
    },
@@ -1071,7 +1071,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "81525791",
+   "id": "9d2f72a1",
    "metadata": {
     "editable": true
    },
@@ -1081,7 +1081,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "42bd4217",
+   "id": "b8413510",
    "metadata": {
     "editable": true
    },
@@ -1093,7 +1093,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "c1f6672f",
+   "id": "0f4bfbf7",
    "metadata": {
     "editable": true
    },
@@ -1103,7 +1103,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "df8c1efa",
+   "id": "85e9df9a",
    "metadata": {
     "editable": true
    },
@@ -1115,7 +1115,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "1b4bf5a8",
+   "id": "a0a9e275",
    "metadata": {
     "editable": true
    },
@@ -1125,7 +1125,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "e2c3ad13",
+   "id": "ecdc2560",
    "metadata": {
     "editable": true
    },
@@ -1137,7 +1137,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "333026af",
+   "id": "85013ea3",
    "metadata": {
     "editable": true
    },
@@ -1147,7 +1147,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "35825027",
+   "id": "e589cff0",
    "metadata": {
     "editable": true
    },
@@ -1159,7 +1159,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "62866612",
+   "id": "4693526c",
    "metadata": {
     "editable": true
    },
@@ -1170,7 +1170,7 @@
   {
    "cell_type": "code",
    "execution_count": 1,
-   "id": "ba11008c",
+   "id": "fe01218c",
    "metadata": {
     "collapsed": false,
     "editable": true
@@ -1194,7 +1194,7 @@
     "    return np.array([2*x[0], 6*x[1]])\n",
     "\n",
     "fig = pt.figure()\n",
-    "ax = fig.gca(projection=\"3d\")\n",
+    "ax = fig.add_subplot(projection = '3d')\n",
     "\n",
     "xmesh, ymesh = np.mgrid[-3:3:50j,-3:3:50j]\n",
     "fmesh = f(np.array([xmesh, ymesh]))\n",
@@ -1203,7 +1203,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "d94f79ff",
+   "id": "fe4f2ad0",
    "metadata": {
     "editable": true
    },
@@ -1214,7 +1214,7 @@
   {
    "cell_type": "code",
    "execution_count": 2,
-   "id": "8d03a29a",
+   "id": "1a31b574",
    "metadata": {
     "collapsed": false,
     "editable": true
@@ -1228,7 +1228,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "1560ce9e",
+   "id": "ea571053",
    "metadata": {
     "editable": true
    },
@@ -1239,7 +1239,7 @@
   {
    "cell_type": "code",
    "execution_count": 3,
-   "id": "444dcac8",
+   "id": "872be7f1",
    "metadata": {
     "collapsed": false,
     "editable": true
@@ -1252,7 +1252,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "6a3a8ba3",
+   "id": "8547fe68",
    "metadata": {
     "editable": true
    },
@@ -1263,7 +1263,7 @@
   {
    "cell_type": "code",
    "execution_count": 4,
-   "id": "96921390",
+   "id": "6a1d1551",
    "metadata": {
     "collapsed": false,
     "editable": true
@@ -1281,7 +1281,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "5090d289",
+   "id": "f9becbe0",
    "metadata": {
     "editable": true
    },
@@ -1292,7 +1292,7 @@
   {
    "cell_type": "code",
    "execution_count": 5,
-   "id": "ac4b2a89",
+   "id": "e65390f0",
    "metadata": {
     "collapsed": false,
     "editable": true
@@ -1307,7 +1307,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "014335b8",
+   "id": "58f1486e",
    "metadata": {
     "editable": true
    },
@@ -1317,7 +1317,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "8f2fc479",
+   "id": "79822d19",
    "metadata": {
     "editable": true
    },
@@ -1331,7 +1331,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "c12ed388",
+   "id": "31ee44af",
    "metadata": {
     "editable": true
    },
@@ -1343,7 +1343,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "525571bd",
+   "id": "d6915e7c",
    "metadata": {
     "editable": true
    },
@@ -1354,7 +1354,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "16ea251e",
+   "id": "e8176ce0",
    "metadata": {
     "editable": true
    },
@@ -1366,7 +1366,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "bc20e247",
+   "id": "5e00591a",
    "metadata": {
     "editable": true
    },
@@ -1377,7 +1377,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "7e393cfd",
+   "id": "fb2da430",
    "metadata": {
     "editable": true
    },
@@ -1388,7 +1388,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "004102f6",
+   "id": "730ce0d7",
    "metadata": {
     "editable": true
    },
@@ -1400,7 +1400,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "842e93a3",
+   "id": "3ab053cd",
    "metadata": {
     "editable": true
    },
@@ -1410,7 +1410,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "988aa113",
+   "id": "3bc30bf4",
    "metadata": {
     "editable": true
    },
@@ -1422,7 +1422,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "6c460be1",
+   "id": "d8ee6bd4",
    "metadata": {
     "editable": true
    },
@@ -1434,7 +1434,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "1694d645",
+   "id": "b77f4e19",
    "metadata": {
     "editable": true
    },
@@ -1446,7 +1446,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "091ad567",
+   "id": "0e2c3a9f",
    "metadata": {
     "editable": true
    },
@@ -1458,7 +1458,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "dd3cf73c",
+   "id": "c023bd9e",
    "metadata": {
     "editable": true
    },
@@ -1469,7 +1469,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "13cf2ad9",
+   "id": "d6436d05",
    "metadata": {
     "editable": true
    },
@@ -1481,7 +1481,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "9bc1ee6e",
+   "id": "46eaa2f8",
    "metadata": {
     "editable": true
    },
@@ -1491,7 +1491,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "05599b4f",
+   "id": "75b26db8",
    "metadata": {
     "editable": true
    },
@@ -1503,7 +1503,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "48dce995",
+   "id": "a403e8b3",
    "metadata": {
     "editable": true
    },
@@ -1513,7 +1513,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "3ed1d31f",
+   "id": "0ec16727",
    "metadata": {
     "editable": true
    },
@@ -1525,7 +1525,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "d53065fb",
+   "id": "9d2ea8a4",
    "metadata": {
     "editable": true
    },
@@ -1545,7 +1545,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "1c9e8acd",
+   "id": "917fc540",
    "metadata": {
     "editable": true
    },
@@ -1557,7 +1557,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "b1ce7e22",
+   "id": "94775878",
    "metadata": {
     "editable": true
    },
@@ -1567,7 +1567,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "5a9d580f",
+   "id": "5c9ba20d",
    "metadata": {
     "editable": true
    },
@@ -1579,7 +1579,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "bd732814",
+   "id": "e0085df3",
    "metadata": {
     "editable": true
    },
@@ -1589,7 +1589,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "a0b6ed43",
+   "id": "34998328",
    "metadata": {
     "editable": true
    },
@@ -1600,7 +1600,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "0647b456",
+   "id": "e01dee5b",
    "metadata": {
     "editable": true
    },
@@ -1612,7 +1612,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "39dd4393",
+   "id": "2048700e",
    "metadata": {
     "editable": true
    },
@@ -1624,7 +1624,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "5d17f7b6",
+   "id": "5301de78",
    "metadata": {
     "editable": true
    },
@@ -1636,7 +1636,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "7f0fbf0c",
+   "id": "d1019da2",
    "metadata": {
     "editable": true
    },
@@ -1649,7 +1649,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "f9d39a67",
+   "id": "fc23feaa",
    "metadata": {
     "editable": true
    },
@@ -1660,7 +1660,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "75e12e7b",
+   "id": "71e65338",
    "metadata": {
     "editable": true
    },
@@ -1672,7 +1672,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "aec178fd",
+   "id": "63e0d868",
    "metadata": {
     "editable": true
    },
@@ -1688,7 +1688,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "d9c2ab58",
+   "id": "ea19d604",
    "metadata": {
     "editable": true
    },
@@ -1700,7 +1700,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "cbe552ed",
+   "id": "33886cb0",
    "metadata": {
     "editable": true
    },
@@ -1711,7 +1711,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "82a132bd",
+   "id": "793adcf2",
    "metadata": {
     "editable": true
    },
@@ -1723,7 +1723,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "0349d81c",
+   "id": "46e45bcb",
    "metadata": {
     "editable": true
    },
@@ -1733,7 +1733,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "7107cbd5",
+   "id": "c3470b7a",
    "metadata": {
     "editable": true
    },
@@ -1745,7 +1745,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "3a56cd7c",
+   "id": "e79f3af5",
    "metadata": {
     "editable": true
    },
@@ -1755,7 +1755,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "63a24c09",
+   "id": "60a4482d",
    "metadata": {
     "editable": true
    },
@@ -1767,7 +1767,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "6ef4ea63",
+   "id": "87bcdceb",
    "metadata": {
     "editable": true
    },
@@ -1777,7 +1777,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "c2357533",
+   "id": "5241b9d6",
    "metadata": {
     "editable": true
    },
@@ -1789,7 +1789,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "61549c12",
+   "id": "b86468ac",
    "metadata": {
     "editable": true
    },
@@ -1813,7 +1813,7 @@
   {
    "cell_type": "code",
    "execution_count": 6,
-   "id": "2bbe00ae",
+   "id": "e09a22a2",
    "metadata": {
     "collapsed": false,
     "editable": true
@@ -1826,7 +1826,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "2edbd94a",
+   "id": "39159e01",
    "metadata": {
     "editable": true
    },
@@ -1837,7 +1837,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "97f601a1",
+   "id": "d37f066c",
    "metadata": {
     "editable": true
    },
@@ -1849,7 +1849,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "46f56da5",
+   "id": "c5b4c22f",
    "metadata": {
     "editable": true
    },
@@ -1859,7 +1859,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "ea40d182",
+   "id": "6a5c726b",
    "metadata": {
     "editable": true
    },
@@ -1871,7 +1871,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "f1529059",
+   "id": "9af4981e",
    "metadata": {
     "editable": true
    },
@@ -1885,7 +1885,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "ff686b79",
+   "id": "df6dbe94",
    "metadata": {
     "editable": true
    },
@@ -1901,7 +1901,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "e9072325",
+   "id": "48733ef7",
    "metadata": {
     "editable": true
    },
@@ -1911,7 +1911,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "b039d2dd",
+   "id": "6dd46b11",
    "metadata": {
     "editable": true
    },
@@ -1923,7 +1923,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "dc1285b8",
+   "id": "3ebd7c3a",
    "metadata": {
     "editable": true
    },
@@ -1933,7 +1933,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "8d029669",
+   "id": "e7ba9d1b",
    "metadata": {
     "editable": true
    },
@@ -1945,7 +1945,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "f2b0be18",
+   "id": "caf55597",
    "metadata": {
     "editable": true
    },
@@ -1959,7 +1959,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "72b959fa",
+   "id": "eae0611f",
    "metadata": {
     "editable": true
    },
@@ -1969,7 +1969,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "53db546f",
+   "id": "b59390fd",
    "metadata": {
     "editable": true
    },
@@ -1980,7 +1980,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "d9799e09",
+   "id": "a5f391b4",
    "metadata": {
     "editable": true
    },
@@ -1995,7 +1995,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "433d7d4e",
+   "id": "e5cb1b8d",
    "metadata": {
     "editable": true
    },
@@ -2005,7 +2005,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "8bcfa1d9",
+   "id": "5f4c54a3",
    "metadata": {
     "editable": true
    },
@@ -2017,7 +2017,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "9591273f",
+   "id": "6484d772",
    "metadata": {
     "editable": true
    },
@@ -2029,7 +2029,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "ff30e5e6",
+   "id": "8a52cb6f",
    "metadata": {
     "editable": true
    },
@@ -2044,7 +2044,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "a58e0dda",
+   "id": "58f1b6fe",
    "metadata": {
     "editable": true
    },
@@ -2057,7 +2057,7 @@
   {
    "cell_type": "code",
    "execution_count": 7,
-   "id": "d6da2734",
+   "id": "9cdfde32",
    "metadata": {
     "collapsed": false,
     "editable": true
@@ -2114,7 +2114,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "a2f94d89",
+   "id": "91c56468",
    "metadata": {
     "editable": true
    },
@@ -2125,7 +2125,7 @@
   {
    "cell_type": "code",
    "execution_count": 8,
-   "id": "f95809e0",
+   "id": "c74ff08d",
    "metadata": {
     "collapsed": false,
     "editable": true
@@ -2152,7 +2152,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "bcca1a86",
+   "id": "5043e2b8",
    "metadata": {
     "editable": true
    },
@@ -2164,7 +2164,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "3f8a3655",
+   "id": "3bd8a0f0",
    "metadata": {
     "editable": true
    },
@@ -2176,7 +2176,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "fe1ae4c5",
+   "id": "775f6562",
    "metadata": {
     "editable": true
    },
@@ -2186,7 +2186,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "75348007",
+   "id": "dbf225a5",
    "metadata": {
     "editable": true
    },
@@ -2200,7 +2200,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "7b401e23",
+   "id": "79933921",
    "metadata": {
     "editable": true
    },
@@ -2210,7 +2210,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "108955a9",
+   "id": "b8600047",
    "metadata": {
     "editable": true
    },
@@ -2222,7 +2222,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "e81e374d",
+   "id": "6554d3a0",
    "metadata": {
     "editable": true
    },
@@ -2233,7 +2233,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "5f670054",
+   "id": "e521b44d",
    "metadata": {
     "editable": true
    },
@@ -2248,7 +2248,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "44190400",
+   "id": "575d42ed",
    "metadata": {
     "editable": true
    },
@@ -2262,7 +2262,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "297e1218",
+   "id": "2dbc9e16",
    "metadata": {
     "editable": true
    },
@@ -2273,7 +2273,7 @@
   {
    "cell_type": "code",
    "execution_count": 9,
-   "id": "f39e42bb",
+   "id": "bf1b1feb",
    "metadata": {
     "collapsed": false,
     "editable": true
@@ -2334,7 +2334,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "d84821a4",
+   "id": "a23c30a6",
    "metadata": {
     "editable": true
    },
@@ -2356,7 +2356,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "386582c7",
+   "id": "55f705f9",
    "metadata": {
     "editable": true
    },
@@ -2369,7 +2369,7 @@
   {
    "cell_type": "code",
    "execution_count": 10,
-   "id": "bdd17d18",
+   "id": "f417edcb",
    "metadata": {
     "collapsed": false,
     "editable": true
@@ -2435,7 +2435,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "6675456b",
+   "id": "8683094d",
    "metadata": {
     "editable": true
    },
@@ -2446,7 +2446,7 @@
   {
    "cell_type": "code",
    "execution_count": 11,
-   "id": "5f7443ae",
+   "id": "7b9579df",
    "metadata": {
     "collapsed": false,
     "editable": true
@@ -2520,7 +2520,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "0c5c47e2",
+   "id": "17ce9f60",
    "metadata": {
     "editable": true
    },
@@ -2532,7 +2532,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "30d83150",
+   "id": "9f088fb4",
    "metadata": {
     "editable": true
    },
@@ -2553,7 +2553,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "310429e5",
+   "id": "5d029aa1",
    "metadata": {
     "editable": true
    },
@@ -2585,7 +2585,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "07ec38f2",
+   "id": "da0f77b7",
    "metadata": {
     "editable": true
    },
@@ -2602,7 +2602,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "79d6fab8",
+   "id": "23113007",
    "metadata": {
     "editable": true
    },
@@ -2615,7 +2615,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "628eb747",
+   "id": "b951ec04",
    "metadata": {
     "editable": true
    },
@@ -2628,7 +2628,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "e1133d46",
+   "id": "f6e1c0da",
    "metadata": {
     "editable": true
    },
@@ -2641,7 +2641,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "4f6e6b79",
+   "id": "21d28fb3",
    "metadata": {
     "editable": true
    },
@@ -2655,7 +2655,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "4c3c9492",
+   "id": "299ca2c9",
    "metadata": {
     "editable": true
    },
@@ -2677,7 +2677,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "8ef691b4",
+   "id": "c951d036",
    "metadata": {
     "editable": true
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@@ -2692,7 +2692,7 @@
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@@ -2704,7 +2704,7 @@
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@@ -2717,7 +2717,7 @@
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@@ -2731,7 +2731,7 @@
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@@ -2742,7 +2742,7 @@
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@@ -2767,7 +2767,7 @@
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@@ -2783,7 +2783,7 @@
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@@ -2804,7 +2804,7 @@
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@@ -2824,7 +2824,7 @@
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@@ -2843,7 +2843,7 @@
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@@ -2878,7 +2878,7 @@
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@@ -2891,7 +2891,7 @@
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@@ -2968,7 +2968,7 @@
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@@ -2983,7 +2983,7 @@
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@@ -2998,7 +2998,7 @@
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@@ -3010,7 +3010,7 @@
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@@ -3028,7 +3028,7 @@
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@@ -3047,7 +3047,7 @@
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@@ -3059,7 +3059,7 @@
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@@ -3069,7 +3069,7 @@
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@@ -3085,7 +3085,7 @@
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@@ -3097,7 +3097,7 @@
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@@ -3107,7 +3107,7 @@
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@@ -3119,7 +3119,7 @@
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@@ -3129,7 +3129,7 @@
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@@ -3141,7 +3141,7 @@
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@@ -3157,7 +3157,7 @@
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@@ -3169,7 +3169,7 @@
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@@ -3202,7 +3202,7 @@
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@@ -3214,7 +3214,7 @@
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@@ -3232,7 +3232,7 @@
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@@ -3242,7 +3242,7 @@
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@@ -3273,7 +3273,7 @@
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@@ -3288,7 +3288,7 @@
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@@ -3306,7 +3306,7 @@
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@@ -3318,7 +3318,7 @@
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@@ -3330,7 +3330,7 @@
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@@ -3348,7 +3348,7 @@
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@@ -3377,7 +3377,7 @@
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@@ -3395,7 +3395,7 @@
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@@ -3407,7 +3407,7 @@
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@@ -3419,7 +3419,7 @@
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@@ -3431,7 +3431,7 @@
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@@ -3443,7 +3443,7 @@
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@@ -3455,7 +3455,7 @@
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@@ -3472,7 +3472,7 @@
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@@ -3491,7 +3491,7 @@
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@@ -3503,7 +3503,7 @@
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@@ -3517,7 +3517,7 @@
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@@ -3537,7 +3537,7 @@
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@@ -3575,7 +3575,7 @@
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@@ -3587,7 +3587,7 @@
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@@ -3597,7 +3597,7 @@
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@@ -3609,7 +3609,7 @@
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@@ -3620,7 +3620,7 @@
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@@ -3665,7 +3665,7 @@
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@@ -3682,7 +3682,7 @@
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@@ -3710,7 +3710,7 @@
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@@ -3725,7 +3725,7 @@
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@@ -3769,7 +3769,7 @@
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@@ -3779,7 +3779,7 @@
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@@ -3790,7 +3790,7 @@
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@@ -3818,7 +3818,7 @@
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@@ -3833,7 +3833,7 @@
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@@ -3844,7 +3844,7 @@
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@@ -3872,7 +3872,7 @@
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@@ -3883,7 +3883,7 @@
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@@ -3908,7 +3908,7 @@
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@@ -3919,7 +3919,7 @@
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@@ -3955,7 +3955,7 @@
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@@ -3975,7 +3975,7 @@
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@@ -3986,7 +3986,7 @@
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@@ -4024,7 +4024,7 @@
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@@ -4034,7 +4034,7 @@
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@@ -4048,7 +4048,7 @@
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@@ -4070,7 +4070,7 @@
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@@ -4080,7 +4080,7 @@
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@@ -4091,7 +4091,7 @@
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@@ -4113,7 +4113,7 @@
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@@ -4126,7 +4126,7 @@
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@@ -4151,7 +4151,7 @@
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@@ -4163,7 +4163,7 @@
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@@ -4178,7 +4178,7 @@
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@@ -4193,7 +4193,7 @@
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@@ -4253,7 +4253,7 @@
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@@ -4264,7 +4264,7 @@
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@@ -4328,7 +4328,7 @@
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@@ -4339,7 +4339,7 @@
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@@ -4388,7 +4388,7 @@
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@@ -4400,7 +4400,7 @@
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@@ -4484,7 +4484,7 @@
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@@ -4495,7 +4495,7 @@
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@@ -4573,7 +4573,7 @@
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@@ -4584,7 +4584,7 @@
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@@ -4643,7 +4643,7 @@
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@@ -4653,7 +4653,7 @@
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@@ -4664,7 +4664,7 @@
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@@ -4729,7 +4729,7 @@
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@@ -4740,7 +4740,7 @@
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    "execution_count": 35,
-   "id": "c32bd5e0",
+   "id": "78763412",
    "metadata": {
     "collapsed": false,
     "editable": true
@@ -4810,7 +4810,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "4183d2b1",
+   "id": "bccda1f8",
    "metadata": {
     "editable": true
    },
@@ -4821,7 +4821,7 @@
   {
    "cell_type": "code",
    "execution_count": 36,
-   "id": "d1a76119",
+   "id": "4febcd9b",
    "metadata": {
     "collapsed": false,
     "editable": true
@@ -4865,7 +4865,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "68fef7c6",
+   "id": "6b50caae",
    "metadata": {
     "editable": true
    },
@@ -4884,7 +4884,7 @@
   {
    "cell_type": "code",
    "execution_count": 37,
-   "id": "d62a782e",
+   "id": "ef30c686",
    "metadata": {
     "collapsed": false,
     "editable": true
diff --git a/doc/src/week39/week39.do.txt b/doc/src/week39/week39.do.txt
index c9d842e63..7f8eb33c1 100644
--- a/doc/src/week39/week39.do.txt
+++ b/doc/src/week39/week39.do.txt
@@ -572,7 +572,7 @@ def df(x):
     return np.array([2*x[0], 6*x[1]])
 
 fig = pt.figure()
-ax = fig.gca(projection="3d")
+ax = fig.add_subplot(projection = '3d')
 
 xmesh, ymesh = np.mgrid[-3:3:50j,-3:3:50j]
 fmesh = f(np.array([xmesh, ymesh]))