How to use the maxminddb.compat.int_from_byte function in maxminddb

def _read_extended(self, offset):
        next_byte = int_from_byte(self._buffer[offset])
        type_num = next_byte + 7
        if type_num < 7:
            raise InvalidDatabaseError(
                "Something went horribly wrong in the decoder. An "
                "extended type resolved to a type number < 8 "
                "({type})".format(type=type_num)
            )
        return type_num, offset + 1

def decode(self, offset):
        """Decode a section of the data section starting at offset

        Arguments:
        offset -- the location of the data structure to decode
        """
        new_offset = offset + 1
        ctrl_byte = int_from_byte(self._buffer[offset])
        type_num = ctrl_byte >> 5
        # Extended type
        if not type_num:
            (type_num, new_offset) = self._read_extended(new_offset)

        try:
            decoder = self._type_decoder[type_num]
        except KeyError:
            raise InvalidDatabaseError(
                "Unexpected type number ({type}) " "encountered".format(type=type_num)
            )

        (size, new_offset) = self._size_from_ctrl_byte(ctrl_byte, new_offset, type_num)
        return decoder(self, size, new_offset)

def _size_from_ctrl_byte(self, ctrl_byte, offset, type_num):
        size = ctrl_byte & 0x1F
        if type_num == 1 or size < 29:
            return size, offset

        if size == 29:
            size = 29 + int_from_byte(self._buffer[offset])
            return size, offset + 1

        # Using unpack rather than int_from_bytes as it is faster
        # here and below.
        if size == 30:
            new_offset = offset + 2
            size_bytes = self._buffer[offset:new_offset]
            size = 285 + struct.unpack(b"!H", size_bytes)[0]
            return size, new_offset

        new_offset = offset + 3
        size_bytes = self._buffer[offset:new_offset]
        size = struct.unpack(b"!I", b"\x00" + size_bytes)[0] + 65821
        return size, new_offset