How to use the telethon.utils.get_peer_id function in Telethon

if isinstance(update, types.UpdateMessageID):
                random_to_id[update.random_id] = update.id

            elif isinstance(update, (
                    types.UpdateNewChannelMessage, types.UpdateNewMessage)):
                update.message._finish_init(self, entities, input_chat)
                id_to_message[update.message.id] = update.message

            elif (isinstance(update, types.UpdateEditMessage)
                  and helpers._entity_type(request.peer) != helpers._EntityType.CHANNEL):
                if request.id == update.message.id:
                    update.message._finish_init(self, entities, input_chat)
                    return update.message

            elif (isinstance(update, types.UpdateEditChannelMessage)
                  and utils.get_peer_id(request.peer) ==
                  utils.get_peer_id(update.message.to_id)):
                if request.id == update.message.id:
                    update.message._finish_init(self, entities, input_chat)
                    return update.message

            elif isinstance(update, types.UpdateNewScheduledMessage):
                update.message._finish_init(self, entities, input_chat)
                sched_to_message[update.message.id] = update.message

            elif isinstance(update, types.UpdateMessagePoll):
                if request.media.poll.id == update.poll_id:
                    m = types.Message(
                        id=request.id,
                        to_id=utils.get_peer(request.peer),
                        media=types.MessageMediaPoll(
                            poll=update.poll,

def add(self, entities):
        """
        Adds the given entities to the cache, if they weren't saved before.
        """
        if not utils.is_list_like(entities):
            # Invariant: all "chats" and "users" are always iterables,
            # and "user" never is (so we wrap it inside a list).
            entities = itertools.chain(
                getattr(entities, 'chats', []),
                getattr(entities, 'users', []),
                (hasattr(entities, 'user') and [entities.user]) or []
            )

        for entity in entities:
            try:
                pid = utils.get_peer_id(entity)
                if pid not in self.__dict__:
                    # Note: `get_input_peer` already checks for `access_hash`
                    self.__dict__[pid] = utils.get_input_peer(entity)
            except TypeError:
                pass

def enqueue_entities(self, entities):
        """
        Enqueues the given iterable of entities to be dumped later by a
        different coroutine. These in turn might enqueue profile photos.
        """
        for entity in entities:
            eid = utils.get_peer_id(entity)
            self._displays[eid] = utils.get_display_name(entity)
            if isinstance(entity, types.User):
                if entity.deleted or entity.min:
                    continue  # Empty name would cause IntegrityError
            elif isinstance(entity, types.Channel):
                if entity.left:
                    continue  # Getting full info triggers ChannelPrivateError
            elif not isinstance(entity, (types.Chat,
                                         types.InputPeerUser,
                                         types.InputPeerChat,
                                         types.InputPeerChannel)):
                # Drop UserEmpty, ChatEmpty, ChatForbidden and ChannelForbidden
                continue

            if eid in self._checked_entity_ids:
                continue

result = await self(functions.updates.GetStateRequest())
                self._state_cache[None] = result.pts, result.date
                return

            result = await self(functions.updates.GetDifferenceRequest(
                pts=pts_date[0],
                date=pts_date[1],
                qts=0
            ))

        if isinstance(result, (types.updates.Difference,
                               types.updates.DifferenceSlice,
                               types.updates.ChannelDifference,
                               types.updates.ChannelDifferenceTooLong)):
            update._entities.update({
                utils.get_peer_id(x): x for x in
                itertools.chain(result.users, result.chats)
            })

raise ValueError(
                        'Cannot get entity from a channel (or group) '
                        'that you are not part of. Join the group and retry'
                    )
                elif isinstance(invite, types.ChatInviteAlready):
                    return invite.chat
            elif username:
                try:
                    result = await self(
                        functions.contacts.ResolveUsernameRequest(username))
                except errors.UsernameNotOccupiedError as e:
                    raise ValueError('No user has "{}" as username'
                                     .format(username)) from e

                try:
                    pid = utils.get_peer_id(result.peer, add_mark=False)
                    if isinstance(result.peer, types.PeerUser):
                        return next(x for x in result.users if x.id == pid)
                    else:
                        return next(x for x in result.chats if x.id == pid)
                except StopIteration:
                    pass
            try:
                # Nobody with this username, maybe it's an exact name/title
                return await self.get_entity(
                    self.session.get_input_entity(string))
            except ValueError:
                pass

        raise ValueError(
            'Cannot find any entity corresponding to "{}"'.format(string)
        )

def get_entity_rows_by_id(self, id, exact=True):
        try:
            if exact:
                return next((id, hash) for found_id, hash, _, _, _
                            in self._entities if found_id == id)
            else:
                ids = (
                    utils.get_peer_id(PeerUser(id)),
                    utils.get_peer_id(PeerChat(id)),
                    utils.get_peer_id(PeerChannel(id))
                )
                return next((id, hash) for found_id, hash, _, _, _
                            in self._entities if found_id in ids)
        except StopIteration:
            pass

async def whichid(event: NewMessage.Event) -> None:
    """
    Get the ID of a chat/channel or user.


    `{prefix}id` or **{prefix}id user1 user2**
    """
    match = event.matches[0].group(1)
    text = ""
    if not match and not event.reply_to_msg_id:
        attr = "first_name" if event.is_private else "title"
        text = f"{getattr(event.chat, attr)}: "
        text += f"`{get_peer_id(event.chat_id)}`"
    elif event.reply_to_msg_id:
        reply = await event.get_reply_message()
        user = reply.sender_id
        if reply.fwd_from:
            if reply.fwd_from.from_id:
                user = reply.fwd_from.from_id
        peer = get_peer_id(user)
        text = f"[{peer}](tg://user?id={peer}): `{peer}`"
    else:
        failed = []
        strings = []
        users, _ = await client.parse_arguments(match)
        for user in users:
            try:
                entity = await client.get_input_entity(user)
                peer = get_peer_id(entity)

def __getitem__(self, item):
        """
        Gets the corresponding :tl:`InputPeer` for the given ID or peer,
        or raises ``KeyError`` on any error (i.e. cannot be found).
        """
        if not isinstance(item, int) or item < 0:
            try:
                return self.__dict__[utils.get_peer_id(item)]
            except TypeError:
                raise KeyError('Invalid key will not have entity') from None

        for cls in (types.PeerUser, types.PeerChat, types.PeerChannel):
            result = self.__dict__.get(utils.get_peer_id(cls(item)))
            if result:
                return result

        raise KeyError('No cached entity for the given key')

def user_id(self):
            """
            Returns the marked signed ID of the first user, if any.
            """
            if self._user_peers:
                return utils.get_peer_id(self._user_peers[0])