how to convert string to byte without encoding python

1import struct
2
3def rawbytes(s):
4    """Convert a string to raw bytes without encoding"""
5    outlist = []
6    for cp in s:
7        num = ord(cp)
8        if num < 255:
9            outlist.append(struct.pack('B', num))
10        elif num < 65535:
11            outlist.append(struct.pack('>H', num))
12        else:
13            b = (num & 0xFF0000) >> 16
14            H = num & 0xFFFF
15            outlist.append(struct.pack('>bH', b, H))
16    return b''.join(outlist)
17

1>>> message = 'test 112 hello: what?!'
2>>> message = message.encode('iso-8859-15')
3>>> message 
4b'test 112 hello: what?!'
5