bug fix

mongodb/source/autograder.py

@@ -88,6 +88,7 @@ def evaluate(query : str):
 
     if query.endswith(';'): query = query[:-1]
     true = True
+    false = False
     data = list(eval(query))
     return [postproc_iter(data, n) if query else None for n in (True, False)]