flatten python's nested sequences

flatten.py

from collections import Iterable


def flatten(items, ignore_types=(str, bytes)):
    """flatten a nested sequence
    implement it based on Python Cookbook(version 3) 4.14 Flattening a Nested Sequence"""
    for x in items:
        if isinstance(x, Iterable) and not isinstance(x, ignore_types):
            yield from flatten(x, ignore_types)
        else:
            yield x