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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 async def get_peer_id(self, peer, add_mark=True):
 """ Gets the ID for the given peer, which may be anything entity-like. This method needs to be ``async`` because `peer` supports usernames, invite-links, phone numbers (from people in your contact list), etc. If ``add_mark is False``, then a positive ID will be returned instead. By default, bot-API style IDs (signed) are returned. """

        if isinstance(peer, int):
            return utils.get_peer_id(peer, add_mark=add_mark)

        try:
            if peer.SUBCLASS_OF_ID not in (0x2d45687, 0xc91c90b6):
                # 0x2d45687, 0xc91c90b6 == crc32(b'Peer') and b'InputPeer'
                peer = await self.get_input_entity(peer)
        except AttributeError:
            peer = await self.get_input_entity(peer)

        if isinstance(peer, types.InputPeerSelf):
            peer = await self.get_me(input_peer=True)

        return utils.get_peer_id(peer, add_mark=add_mark)