collections.defaultdict: Make __missing__() behavior more compliant.

https://docs.python.org/3.3/library/collections.html#collections.defaultdict.__missing__
says that it's __missing__() what should check default_factory for None
(so this entire behavior can be overriden in subclasses).

collections.defaultdict/collections/defaultdict.py

@@ -8,8 +8,6 @@ class defaultdict:
         try:
             return self.d[key]
         except KeyError:
-            if self.default_factory is None:
-                raise
             v = self.__missing__(key)
             self.d[key] = v
             return v
@@ -21,4 +19,6 @@ class defaultdict:
         del self.d[key]
 
     def __missing__(self, key):
+        if self.default_factory is None:
+            raise KeyError(key)
         return self.default_factory()

collections.defaultdict/setup.py

@@ -1,7 +1,7 @@
 from distutils.core import setup
 
 setup(name='micropython-collections.defaultdict',
-      version='0.1',
+      version='0.2',
       description='collections.defaultdict module for MicroPython',
       url='https://github.com/micropython/micropython/issues/405',
       author='Paul Sokolovsky',