def _bytesToIPv4(bytestring):
        """
        Convert packed 32-bit IPv4 address bytes into a dotted-quad ASCII bytes
        representation of that address.

        @param bytestring: 4 octets representing an IPv4 address.
        @type bytestring: L{bytes}

        @return: a dotted-quad notation IPv4 address.
        @rtype: L{bytes}
        """
        return b'.'.join(
            ('%i' % (ord(b),)).encode('ascii')
            for b in compat.iterbytes(bytestring)
        )

        Convert packed 32-bit IPv4 address bytes into a dotted-quad ASCII bytes
        representation of that address.

        @param bytestring: 4 octets representing an IPv4 address.
        @type bytestring: L{bytes}

        @return: a dotted-quad notation IPv4 address.
        @rtype: L{bytes}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/protocols/haproxy/_v2parser.py