Get rid of the None default for memoize_default. It shouldn't have a default if not given. This also uncovered a bug in for/else loops, that wasn't teste before.

test/completion/basic.py

@@ -105,6 +105,13 @@ for i in b:
 #? float() str()
 a[0]
 
+for i in [1,2,3]:
+    #? int()
+    i
+else:
+    i
+
+
 # -----------------
 # range()
 # -----------------