correct bit complement operation in python (it doesn't seem to work as expected - i.e. on unsigned value - or byte value)

bitops.py

# coding: utf-8
'''
Tried to bit-invert a CSS hex-encoded color using python, but
couldn't get expected output with bit-invert operator.
I.e. this didn't do what I expected:

    print(f'#{old_color:x} => #{~old_color:x}')

Besides acting on an apparently arbitrary length integer (rather
than an unsigned (i.e. sign-not-interpreted) bit pattern, the operator
also only (!) works on integers - but not bytes.

This did it, is one solution.

example usage:

    old_color = 0x83fdcc
    print(f'#{old_color:x} => #{bit_invert(old_color):x}')
'''
def byte_mask(v):
    '''
    returns a byte mask for the byte_length of v,
    e.g.  for a 2 byte value, returns 0xffff

    '''
    n = v.bit_length()
    # ensure #bits is an integral of 8
    shift_bits = n if n%8 ==0 else (n//8+1)*8
    return (1<<shift_bits)-1


bit_invert = lambda v: ~v&byte_mask(v)