'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}'

@staticmethod
def _bytesToIPv4(bytestring):

    return '.'.join((('%i' % (ord(b),)).encode('ascii') for b in compat.iterbytes(bytestring)))
