Method add

lib/sqlalchemy/orm/identity.py:181–205

(self, state: InstanceState[Any])

        return existing

    def add(self, state: InstanceState[Any]) -> bool:
        key = state.key
        assert key is not None
        # inline of self.__contains__
        if key in self._dict:
            try:
                existing_state = self._dict[key]
            except KeyError:
                # catch gc removed the key after we just checked for it
                pass
            else:
                if existing_state is not state:
                    o = existing_state.obj()
                    if o is not None:
                        raise sa_exc.InvalidRequestError(
                            "Can't attach instance "
                            "%s; another instance with key %s is already "
                            "present in this session."
                            % (orm_util.state_str(state), state.key)
                        )
                else:
                    return False
        self._dict[key] = state
        self._manage_incoming_state(state)
        return True

    def _add_unpresent(
        self, state: InstanceState[Any], key: _IdentityKeyType[Any]