def set_tcp_flags(self, tcp_flags):
        """Set the complete tcp flag bitmask"""

        if tcp_flags < 0 or tcp_flags > 255:
            raise ValueError("Invalid tcp_flags. Valid: 0-255.")

        prev_size = 0
        if self._json_dict.get('tcp_flags') is not None:
            prev_size = len(str(self._json_dict['tcp_flags'])) + len('tcp_flags') + 3  # str, key, key quotes, colon

        self._json_dict['tcp_flags'] = tcp_flags

        # update size
        new_size = len(str(self._json_dict['tcp_flags'])) + len('tcp_flags') + 3  # str, key, key quotes, colon
        self._size += new_size - prev_size

        if prev_size == 0 and self._has_field:
            # add the comma and space
            self._size += 2
        self._has_field = True
Set the complete tcp flag bitmask