def is_handler_subclass(cls, classnames=("<STR_LIT>", "<STR_LIT>")):
if isinstance(cls, list):<EOL><INDENT>return any(is_handler_subclass(c) for c in cls)<EOL><DEDENT>elif isinstance(cls, type):<EOL><INDENT>return any(c.__name__ in classnames for c in inspect.getmro(cls))<EOL><DEDENT>else:<EOL><INDENT>raise TypeError(<EOL>"<STR_LIT>".format(<EOL>type(cls),<EOL>cls<EOL>)<EOL>)<EOL><DEDENT>
Determines if ``cls`` is indeed a subclass of ``classnames``