def add(self, name, value):
        """Adds a new value for the given key."""
        norm_name = _normalized_headers[name]
        self._last_key = norm_name
        if self in norm_name:
            # bypass our override of __setitem__ since it modifies _as_list
            dict.__setitem__(self, norm_name,
                             native_str(self[norm_name]) + ',' +
                             native_str(value))
            self._as_list[norm_name].append(value)
        else:
            self[norm_name] = value
dataset/ETHPy150Open RobotWebTools/rosbridge_suite/rosbridge_server/src/tornado/httputil.py/HTTPHeaders.add/swapped operands of `in`