def pad_dgram_four_bytes(self, dgram):
    'Pad a datagram up to a multiple of 4 bytes.'
    return (dgram + (b'\x00' * (4 - (len(dgram) % 4))))
Pad a datagram up to a multiple of 4 bytes.
def pad_dgram_four_bytes(self, dgram):
    
    return (dgram + (b'\x00' * (4 - (len(dgram) % 4))))