@classmethod<EOL><INDENT>def register_type(cls, propname, valcls, objcls=None):<DEDENT>
<EOL>if objcls is None:<EOL><INDENT>objcls = cls<EOL><DEDENT>typemap = cls._types.get(objcls, None)<EOL>if not typemap:<EOL><INDENT>typemap = {}<EOL>cls._types[objcls] = typemap<EOL><DEDENT>typemap[propname] = valcls<EOL>
register type for class 

:param cls:
:param propname:
:param valcls:
:param objcls: