Return instance of todo that has been added.

Returns None when no todo item was added.

TodoList.py

@@ -94,6 +94,7 @@ class TodoList(object):
         Then there will be an edge 1 --> 2 with ID 4.
         """
 
+        todo = None
         if re.search(r'\S', p_src):
             number = len(self._todos) + 1
             todo = Todo.Todo(p_src, number)
@@ -101,6 +102,8 @@ class TodoList(object):
 
             self._maintain_dep_graph(todo)
 
+        return todo
+
     def delete(self, p_number):
         """ Deletes a todo item from the list. """
         todo = self.todo(p_number)