diff --git a/jedi/modules.py b/jedi/modules.py
index 035a894e..4a66d477 100644
--- a/jedi/modules.py
+++ b/jedi/modules.py
@@ -92,7 +92,7 @@ class ModuleWithCursor(Module):
     :param position: The position, the user is currently in. Only important \
     for the main file.
     """
-    def __init__(self, path, source, position, fast):
+    def __init__(self, path, source, position, fast=True):
         super(ModuleWithCursor, self).__init__(path, source)
         self._parserclass = fast_parser.FastParser if fast else \
                             parsing.Parser