def connect(self, receiver, signal, **kwargs):
        """
        Connect a receiver function to a signal.

        The signal can be any object, although Scrapy comes with some
        predefined signals that are documented in the :ref:`topics-signals`
        section.

        :param receiver: the function to be connected
        :type receiver: callable

        :param signal: the signal to connect to
        :type signal: object
        """
        kwargs.setdefault('sender', self.sender)
        return dispatcher.connect(receiver, signal, **kwargs)

        Connect a receiver function to a signal.

        The signal can be any object, although Scrapy comes with some
        predefined signals that are documented in the :ref:`topics-signals`
        section.

        :param receiver: the function to be connected
        :type receiver: callable

        :param signal: the signal to connect to
        :type signal: object
        
stackoverflow/venv/lib/python3.6/site-packages/scrapy/signalmanager.py