code: def readline(self) -> bytes:
          '''Read a line of data.'''
          assert self._state == ConnectionState.created, \
              'Expect conn created. Got {}.'.format(self._state)
  
          with self._close_timer.with_timeout():
              data = yield from \
                  self.run_network_operation(
                      self.reader.readline(),
                      close_timeout=self._timeout,
                      name='Readline')
  
          return datf readline(self) -> bytes:
          '''Read a line of data.'''
          assert self._state == ConnectionState.created, \
              'Expect conn created. Got {}.'.format(self._state)
  
          with self._close_timer.with_timeout():
              data = yield from \
                  self.run_network_operation(
                      self.reader.readline(),
                      close_timeout=self._timeout,
                      name='Readline')
  
          return data
docs: Read a line of data.