small omission in code

doc/src/week45/week45.do.txt

@@ -40,6 +40,7 @@ from pydot import graph_from_dot_data
 from sklearn.datasets import load_breast_cancer
 from sklearn.svm import SVC
 from sklearn.linear_model import LogisticRegression
+from sklearn.tree import DecisionTreeClassifier
 from sklearn.ensemble import RandomForestClassifier
 from sklearn.preprocessing import LabelEncoder
 from sklearn.model_selection import cross_validate