code: def input_sender(self):
          
          if self._input_sender is None and self._sender_id:
              try:
                  self._input_sender = self._client.session\
                      .get_input_entity(self._sender_id)
              except ValueError:
                  pass
          return self._input_sender
docs: This :tl:`InputPeer` is the input version of the user/channel who
          sent the message. Similarly to `input_chat`, 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 can't
          find the input chat, or if the message a broadcast on a channel.