def METHOD_NAME(obj):
	mod = obj.__class__.__module__
	if mod == '__main__':
		mod = None
		warnings.warn(('class {0:} seems to have been defined in the main file; unfortunately this means'
			' that it\'s module/import path is unknown, so you might have to provide cls_lookup_map when '
			'decoding').format(obj.__class__))
	return mod