import collections
dir(collections)
>>['Callable', 'Container', 'Counter', 'Hashable',
'ItemsView', 'Iterable', 'Iterator', 'KeysView',
'Mapping', 'MappingView',
'MutableMapping', 'MutableSequence', 'MutableSet',
'OrderedDict', 'Sequence', 'Set', 'Sized', 'ValuesView',
'__all__', '__builtins__', '__doc__', '__file__', '__name__', '__package__', '_abcoll', '_chain', '_class_template', '_eq', '_field_template', '_get_ident',
'_heapq', '_imap', '_iskeyword', '_itemgetter',
'_repeat', '_repr_template', '_starmap', '_sys',
'defaultdict', 'deque', 'namedtuple']
https://www.liaoxuefeng.com/wiki/0014316089557264a6b348958f449949df42a6d3a2e542c000/001431953239820157155d21c494e5786fce303f3018c86000