from collections import Iterable def flatten(items): for x in items: if isinstance(x, Iterable) and not isinstance(x, (str, bytes)): yield from flatten(x) else: yield x
"""
>>> items = [1, 2, [3, 4, [5, 6], 7], 8]
>>> flatten(items)
<generator object flatten at 0x73bd9c>
>>> list(flatten(items))
[1, 2, 3, 4, 5, 6, 7, 8]
>>> mixed_bag = [1, 'spam', 2, [3, 'eggs', 4], {'x': 1, 'y': 2}]
>>> list(flatten(mixed_bag))
[1, 'spam', 2, 3, 'eggs', 4, 'y', 'x']
"""