<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _run(self):
 """ Run the task respecting dependencies """

        for node in self.node.relatives:
            launch_node_task(node)
        for node in self.node.relatives:
            self.wait_and_join(node.task)
        if self.node.parent:
            while not self.node.parent.task.siblings_permission:
                time.sleep(self._polling_time)
        self.has_started = True
        self.main()
        self.siblings_permission = True
        for node in self.node.siblings:
            launch_node_task(node)
        for node in self.node.siblings:
            self.wait_and_join(node.task)
        self.finished_at = time.time()
        self.scheduler.notify_execution(self)
        self.has_finished = True