def remove_extension(module, name, code):
key = (module, name)<EOL>if (_extension_registry.get(key) != code or<EOL>_inverted_registry.get(code) != key):<EOL><INDENT>raise ValueError("<STR_LIT>" %<EOL>(key, code))<EOL><DEDENT>del _extension_registry[key]<EOL>del _inverted_registry[code]<EOL>if code in _extension_cache:<EOL><INDENT>del _extension_cache[code]<EOL><DEDENT>
Unregister an extension code.  For testing only.