How to use the synapse.api.constants.EventTypes function in synapse

pagination_handler._purges_by_id[purge_id] = PurgeStatus()
        self.get_success(
            pagination_handler._purge_history(
                purge_id=purge_id,
                room_id=self.room_id,
                token=second_token,
                delete_local_events=True,
            )
        )

        # Check that we only get the second message through /message now that the first
        # has been purged.
        request, channel = self.make_request(
            "GET",
            "/rooms/%s/messages?access_token=x&from=%s&dir=b&filter=%s"
            % (self.room_id, second_token, json.dumps({"types": [EventTypes.Message]})),
        )
        self.render(request)
        self.assertEqual(channel.code, 200, channel.json_body)

        chunk = channel.json_body["chunk"]
        self.assertEqual(len(chunk), 1, [event["content"] for event in chunk])

        # Check that we get no event, but also no error, when querying /messages with
        # the token that was pointing at the first event, because we don't have it
        # anymore.
        request, channel = self.make_request(
            "GET",
            "/rooms/%s/messages?access_token=x&from=%s&dir=b&filter=%s"
            % (self.room_id, first_token, json.dumps({"types": [EventTypes.Message]})),
        )
        self.render(request)

def inject_room_member(
        self, room, user, membership, replaces_state=None, extra_content={}
    ):
        content = {"membership": membership}
        content.update(extra_content)
        builder = self.event_builder_factory.for_room_version(
            RoomVersions.V1,
            {
                "type": EventTypes.Member,
                "sender": user.to_string(),
                "state_key": user.to_string(),
                "room_id": room.to_string(),
                "content": content,
            },
        )

        event, context = self.get_success(
            self.event_creation_handler.create_new_client_event(builder)
        )

        self.get_success(self.storage.persistence.persist_event(event, context))

        return event

def get_create_event_for_room(self, room_id):
        """Get the create state event for a room.

        Args:
            room_id (str)

        Returns:
            Deferred[EventBase]: The room creation event.

        Raises:
            NotFoundError if the room is unknown
        """
        state_ids = yield self.get_current_state_ids(room_id)
        create_id = state_ids.get((EventTypes.Create, ""))

        # If we can't find the create event, assume we've hit a dead end
        if not create_id:
            raise NotFoundError("Unknown room %s" % (room_id))

        # Retrieve the room's create event and return
        create_event = yield self.get_event(create_id)
        return create_event

state_ids = {}
                if lazy_load_members:
                    if members_to_fetch and batch.events:
                        # We're returning an incremental sync, with no
                        # "gap" since the previous sync, so normally there would be
                        # no state to return.
                        # But we're lazy-loading, so the client might need some more
                        # member events to understand the events in this timeline.
                        # So we fish out all the member events corresponding to the
                        # timeline here, and then dedupe any redundant ones below.

                        state_ids = yield self.store.get_state_ids_for_event(
                            batch.events[0].event_id,
                            # we only want members!
                            state_filter=StateFilter.from_types(
                                (EventTypes.Member, member)
                                for member in members_to_fetch
                            ),
                        )

            if lazy_load_members and not include_redundant_members:
                cache_key = (sync_config.user.to_string(), sync_config.device_id)
                cache = self.get_lazy_loaded_members_cache(cache_key)

                # if it's a new sync sequence, then assume the client has had
                # amnesia and doesn't want any recent lazy-loaded members
                # de-duplicated.
                if since_token is None:
                    logger.debug("clearing LruCache for %r", cache_key)
                    cache.clear()
                else:
                    # only send members which aren't in our LruCache (either

# Check if old room was non-federatable

        # Get old room's create event
        old_room_create_event = yield self.store.get_create_event_for_room(old_room_id)

        # Check if the create event specified a non-federatable room
        if not old_room_create_event.content.get("m.federate", True):
            # If so, mark the new room as non-federatable as well
            creation_content["m.federate"] = False

        initial_state = dict()

        # Replicate relevant room events
        types_to_copy = (
            (EventTypes.JoinRules, ""),
            (EventTypes.Name, ""),
            (EventTypes.Topic, ""),
            (EventTypes.RoomHistoryVisibility, ""),
            (EventTypes.GuestAccess, ""),
            (EventTypes.RoomAvatar, ""),
            (EventTypes.Encryption, ""),
            (EventTypes.ServerACL, ""),
            (EventTypes.RelatedGroups, ""),
        )

        old_room_state_ids = yield self.store.get_filtered_current_state_ids(
            old_room_id, StateFilter.from_types(types_to_copy),
        )
        # map from event_id to BaseEvent
        old_room_state_events = yield self.store.get_events(old_room_state_ids.values())

# event_edges tables.
        self._handle_mult_prev_events(
            txn, events=[event for event, _ in events_and_contexts]
        )

        for event, _ in events_and_contexts:
            if event.type == EventTypes.Name:
                # Insert into the event_search table.
                self._store_room_name_txn(txn, event)
            elif event.type == EventTypes.Topic:
                # Insert into the event_search table.
                self._store_room_topic_txn(txn, event)
            elif event.type == EventTypes.Message:
                # Insert into the event_search table.
                self._store_room_message_txn(txn, event)
            elif event.type == EventTypes.Redaction:
                # Insert into the redactions table.
                self._store_redaction(txn, event)
            elif event.type == EventTypes.Retention:
                # Update the room_retention table.
                self._store_retention_policy_for_room_txn(txn, event)

            self._handle_event_relations(txn, event)

            # Store the labels for this event.
            labels = event.content.get(EventContentFields.LABELS)
            if labels:
                self.insert_labels_for_event_txn(
                    txn, event.event_id, labels, event.room_id, event.depth
                )

        # Insert into the room_memberships table.

def _is_invite_via_3pid(event):
    return (
        event.type == EventTypes.Member
        and event.membership == Membership.INVITE
        and "third_party_invite" in event.content
    )

content={"alias": room_alias.to_string()},
            )

        if (EventTypes.JoinRules, "") not in initial_state:
            yield send(
                etype=EventTypes.JoinRules, content={"join_rule": config["join_rules"]}
            )

        if (EventTypes.RoomHistoryVisibility, "") not in initial_state:
            yield send(
                etype=EventTypes.RoomHistoryVisibility,
                content={"history_visibility": config["history_visibility"]},
            )

        if config["guest_can_join"]:
            if (EventTypes.GuestAccess, "") not in initial_state:
                yield send(
                    etype=EventTypes.GuestAccess, content={"guest_access": "can_join"}
                )

        for (etype, state_key), content in initial_state.items():
            yield send(etype=etype, state_key=state_key, content=content)

current_member_id = current_state_ids.get((EventTypes.Member, user_id))
            if not current_member_id:
                continue

            # mapping from event_id -> state_dict
            prev_state_ids = yield self.store.get_state_ids_for_events(event_ids)

            # Check if we've joined the room? If so we just blindly add all the users to
            # the "possibly changed" users.
            for state_dict in itervalues(prev_state_ids):
                member_event = state_dict.get((EventTypes.Member, user_id), None)
                if not member_event or member_event != current_member_id:
                    for key, event_id in iteritems(current_state_ids):
                        etype, state_key = key
                        if etype != EventTypes.Member:
                            continue
                        possibly_changed.add(state_key)
                    break

            # If there has been any change in membership, include them in the
            # possibly changed list. We'll check if they are joined below,
            # and we're not toooo worried about spuriously adding users.
            for key, event_id in iteritems(current_state_ids):
                etype, state_key = key
                if etype != EventTypes.Member:
                    continue

                # check if this member has changed since any of the extremities
                # at the stream_ordering, and add them to the list if so.
                for state_dict in itervalues(prev_state_ids):
                    prev_event_id = state_dict.get(key, None)

logger.info("Sending %s in new room", EventTypes.Member)
        yield self.room_member_handler.update_membership(
            creator,
            creator.user,
            room_id,
            "join",
            ratelimit=False,
            content=creator_join_profile,
        )

        # We treat the power levels override specially as this needs to be one
        # of the first events that get sent into a room.
        pl_content = initial_state.pop((EventTypes.PowerLevels, ''), None)
        if pl_content is not None:
            yield send(
                etype=EventTypes.PowerLevels,
                content=pl_content,
            )
        else:
            power_level_content = {
                "users": {
                    creator_id: 100,
                },
                "users_default": 0,
                "events": {
                    EventTypes.Name: 50,
                    EventTypes.PowerLevels: 100,
                    EventTypes.RoomHistoryVisibility: 100,
                    EventTypes.CanonicalAlias: 50,
                    EventTypes.RoomAvatar: 50,
                },
                "events_default": 0,