code: def connect(self, coro):
          
          self.logger.debug("connecting %r", coro)
          return self._connect(coro)
docs: The coroutine `coro` is connected to the signal. The coroutine must
          return a true value, unless it wants to be disconnected from the
          signal.
  
          .. note::
  
             This is different from the return value convention with
             :attr:`AdHocSignal.STRONG` and :attr:`AdHocSignal.WEAK`.
  
          :meth:`connect` returns a token which can be used with
          :meth:`disconnect` to disconnect the coroutine.