code: def input_chat(self):
          
          if self._input_chat is None and self._chat_peer:
              try:
                  self._input_chat = self._client._entity_cache[self._chat_peer]
              except KeyError:
                  pass
  
          return self._input_chat
docs: This :tl:`InputPeer` is the input version of the chat where the
          message was sent. Similarly to `input_sender`, this doesn't have
          things like username or similar, but still useful in some cases.
  
          Note that this might not be available if the library doesn't
          have enough information available.