See :meth:`~pluginsmanager.observer.observable_list.ObservableList.pop()` method

def pop(self, index=None):
        """
        See :meth:`~pluginsmanager.observer.observable_list.ObservableList.pop()` method
        """
        if index is None:
            index = len(self.real_list) - 1

        effect = self[index]
        returned = self.real_list.pop(index)

        self._items.remove(effect)
        return returned