code: def write(self, data):
          
          if not isinstance(data, (bytes, bytearray, memoryview)):
              raise TypeError('data argument must be byte-ish (%r)',
                              type(data))
  
          if not self._state.is_writable or self._closing:
              raise self._invalid_state("write() called")
  
          if not data:
              return
  
          if not self._buffer:
              self._loop.add_writer(self._raw_fd, self._write_ready)
  
          self._buffer.extend(data)
docs: Write data to the transport. This is an invalid operation if the stream
          is not writable, that is, if it is closed. During TLS negotiation, the
          data is buffered.