Raise an exception if code_path is not one of our
        whitelisted valid_paths.

def validate_code_path(valid_paths, code_path, **kw):
        """ Raise an exception if code_path is not one of our
        whitelisted valid_paths.
        """

        root, name = code_path.split(':', 1)
        if name not in valid_paths[root]:
            raise ValueError("%r is not a valid code_path" % code_path)