You're reading the pure-python version of operator.py. You get the builtin versions of the same functions - not the python functions when you use it - see the import of _operator further down the file.

Also verify the type info on the object here:

  In [1]: import operator
  In [5]: operator.add??
  Signature: operator.add(a, b, /)
  Docstring: Same as a + b.
  Type:      builtin_function_or_method