def getCookie(key):
        """
        Get a cookie that was sent from the network.

        @type key: L{bytes}
        @param key: The name of the cookie to get.

        @rtype: L{bytes} or L{None}
        @returns: The value of the specified cookie, or L{None} if that cookie
            was not present in the request.
        """

        Get a cookie that was sent from the network.

        @type key: L{bytes}
        @param key: The name of the cookie to get.

        @rtype: L{bytes} or L{None}
        @returns: The value of the specified cookie, or L{None} if that cookie
            was not present in the request.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/iweb.py