python package `from _collections import deque, defaultdict`

Question

I saw this line of code by chance yesterday
from _collections import deque

I was looking at the python library documentation. When I saw collections, I went to find the source code of deque.
Then I looked for _collections, but it was not found in the Lib directory. Use the search file When I found the directory
Lib/site-packages/requests/packages/urllib3/_collections.py , but there was no code about deque in it, so I was curiousfrom _collections import deque, where did this _collections come from

Answer 1

here

https://github.com/python/cpy...

Answer 2

Built-in module, similar to c extension

In [4]: ​​import _collections

In [5]: _collections
Out[5]: <module '_collections' (built-in)>

Answer 3

_collections是一个内置模块, 要从源码查找: Python-2.7.12/Modules/_collectionsmodule.c