@listener.setter  <EOL><INDENT>def listener(self, listener):<DEDENT>
self.__listener = listener<EOL>
Object that receives updates.

        This should be an object implementing two methods:
        - playstatus_update(updater, playstatus)
        - playstatus_error(updater, exception)

        The first method is called when a new update happens and the second one
        is called if an error occurs. Please note that if an error happens,
        push updates will be stopped. So they will need to be enabled again,
        e.g. from the error method. A delay should preferably be passed to
        start() to avoid an infinite error-loop.