def METHOD_NAME(self):
    # ACHTUNG! All running requests must always be cancelled first to prevent race condition!
    for rq in self.root_requests_list:
        rq.cancel()
    self.dialog_widget.channels_tree_wt.clear()
    self.id2wt_mapping = {0: self.dialog_widget.channels_tree_wt}
    self.load_channel(0)