I've performed the following in the Python 3.7.0 interpreter:
>>> test = pack('<8s', b'\x00\x01\x00\x02\x00\x00\x00\x03')
>>> test
b'\x00\x01\x00\x02\x00\x00\x00\x03'
>>> type(test)
<class 'bytes'>
>>> unpack('>8s', test)
(b'\x00\x01\x00\x02\x00\x00\x00\x03',)
>>> unpack('<8s', test)
(b'\x00\x01\x00\x02\x00\x00\x00\x03',)
Expected behavior: When I run unpack with big endian specified, the unpack returns the bytes in the reverse order from the original input which is packed with little endian.
Actual behavior: The bytes never change order at all.