no_str_iterable.py

import collections


class NoStrIterable(collections.Iterable):

    """
    'isinstance(smt, NoStrIterable)'
        instead of
    'isinstance(smt, collection.Iterable) and not isinstance(smt, str)'
    """

    @classmethod
    def __subclasshook__(cls, obj):
        return (
            not issubclass(obj, (str, bytes))
            and collections.Iterable.__subclasshook__(obj)
        )