[Python] defaultdict `.get` returns item and not none after calling after `[]` operator

I ran this code:

from collections import defaultdict
my_dict = defaultdict(lambda: 6, a=7)
print(repr(my_dict.get("a")))
print(repr(my_dict.get("b")))
print(repr(my_dict["b"]))
print(repr(my_dict.get("b")))


And the output was:

7
None
6
6


Ran it on: 3.13.1 (tags/v3.13.1:0671451, Dec 3 2024, 19:06:28) [MSC v.1942 64 bit (AMD64)].

As you can see, when I called my_dict.get("b") before calling my_dict["b"], it returned None. But after I called my_dict.get("b"), it returned None.

According to the docs, it should return the default computed by the factory only at the my_dict["b"] call (__getitem__() method), so why at the second call of: my_dict.get("b"), it returned the computed value? Is it an expected value, or a bug?

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