Simplify list trainer code.

chatterbot/training/trainers.py

@@ -5,7 +5,6 @@
 class Trainer(object):
 
     def __init__(self, storage, **kwargs):
-        self.kwargs = kwargs
         self.storage = storage
         self.corpus = Corpus()
 
@@ -15,23 +14,27 @@ def train(self):
 
 class ListTrainer(Trainer):
 
+    def get_or_create(self, statement_text):
+        """
+        Return a statement if it exists.
+        Create and return the statement if it does not exist.
+        """
+        statement = self.storage.find(statement_text)
+
+        if not statement:
+            statement = Statement(statement_text)
+
+        return statement
+
     def train(self, conversation):
         statement_history = []
 
         for text in conversation:
-            statement = self.storage.find(text)
+            statement = self.get_or_create(text)
 
-            # Create the statement if a match was not found
-            if not statement:
-                statement = Statement(text)
-
-            previous_statement = None
             if statement_history:
-                previous_statement = statement_history[-1]
-
-            if previous_statement:
                 statement.add_response(
-                    Response(previous_statement.text)
+                    Response(statement_history[-1].text)
                 )
 
             statement_history.append(statement)