Check individual argument (list/tuple/string/etc)

def _check_arg(self, arg):
        """ Check individual argument (list/tuple/string/etc) """
        if isinstance(arg, list):
            return self._get_dependencies_from_args(arg)
        elif isinstance(arg, dict):
            return self._get_dependencies_from_kwargs(arg)

        if not is_dependency_name(arg):
            return set()
        return set([arg[1:]])