don't load sklearn libraries unless needed

src/documents/classifier.py

@@ -5,10 +5,6 @@ import pickle
 import re
 
 from django.conf import settings
-from sklearn.feature_extraction.text import CountVectorizer
-from sklearn.neural_network import MLPClassifier
-from sklearn.preprocessing import MultiLabelBinarizer, LabelBinarizer
-from sklearn.utils.multiclass import type_of_target
 
 from documents.models import Document, MatchingModel
 
@@ -109,6 +105,10 @@ class DocumentClassifier(object):
             pickle.dump(self.document_type_classifier, f)
 
     def train(self):
+        from sklearn.feature_extraction.text import CountVectorizer
+        from sklearn.neural_network import MLPClassifier
+        from sklearn.preprocessing import MultiLabelBinarizer, LabelBinarizer
+
         data = list()
         labels_tags = list()
         labels_correspondent = list()
@@ -265,6 +265,8 @@ class DocumentClassifier(object):
             return None
 
     def predict_tags(self, content):
+        from sklearn.utils.multiclass import type_of_target
+
         if self.tags_classifier:
             X = self.data_vectorizer.transform([preprocess_content(content)])
             y = self.tags_classifier.predict(X)