tools and fixes

bind/.gitignore

@@ -1 +1,2 @@
 minicalo.cpython-38-x86_64-linux-gnu.so
+tmp_test*

bind/G4Calo.py

@@ -398,3 +398,8 @@ def display_event(gd : GeometryDescriptor,
         fig.show(renderer=renderer) 
     else:
         fig.show() 
+
+
+
+def to_numpy(df_column):
+    return np.array(df_column.tolist())