import enum

class bitmap(enum.IntFlag):
    pass

print(bitmap.from_bytes(b'\x00', 'little'))

Traceback (most recent call last):
  File "/.../cpython/test.py", line 6, in <module>
    print(bitmap.from_bytes(b'\x00', 'little'))
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/.../cpython/Lib/enum.py", line 742, in __call__
    return cls._create_(
           ^^^^^^^^^^^^^
  File "/.../cpython/Lib/enum.py", line 870, in _create_
    for item in names:
TypeError: 'NoneType' object is not iterable