https://github.com/apache/airflow/blob/main/airflow/cli/commands/task_command.py#L145
child_instances = [
                    item
                    for sublist in (child["instances"] for child in children if "instances" in child)
                    for item in sublist
                    if item and item["run_id"] == run_id
                ]
                children_queued_dttms = (item["queued_dttm"] for item in child_instances)
                children_start_dates = (item["start_date"] for item in child_instances)
                children_end_dates = (item["end_date"] for item in child_instances)
                children_states = {item["state"] for item in child_instances}
                
                
                
                mapped_states: MutableMapping[str, int] = defaultdict(int)
                for mi_values in mapped_instances.values():
                    child_states = {mi.state for mi in mi_values}
                    state = next(s for s in wwwutils.priority if s in child_states)
                    value = state.value if state is not None else "no_status"
                    mapped_states[value] += 1
                group_state = next((state for state in wwwutils.priority if state in children_states), None)
                group_queued_dttm = min(filter(None, children_queued_dttms), default=None)
                group_start_date = min(filter(None, children_start_dates), default=None)
                group_end_date = max(filter(None, children_end_dates), default=None)
                return {
                    "task_id": task_group.group_id,
                    "run_id": run_id,
                    "state": group_state,
                    "queued_dttm": group_queued_dttm,
                    "start_date": group_start_date,
                    "end_date": group_end_date,