'Method used to get the status of pool resource.
This method is used to get the status of the pool
resources belonged to the specific Load Balancer.
:param loadbalancer_id: The ID of the Load Balancer.
:param parent_id: The parent ID of the pool resource.
:returns: The status dictionary of the pool resource.
The key is the ID of the pool resource. The value is
the operating status of the pool resource.'

def _get_pool_status(self, loadbalancer_id, parent_id):

    resp = self._retrieve_loadbalancer_status_tree(loadbalancer_id)
    status_tree = resp.get('statuses').get('loadbalancer')
    status_dict = dict()
    listeners_status = status_tree.get('listeners')
    for listener_status in listeners_status:
        listener_id = listener_status.get('id')
        if (listener_id == parent_id):
            pools_status = listener_status.get('pools')
            for pool_status in pools_status:
                key = pool_status.get('id')
                if (key is None):
                    continue
                value = pool_status.get('operating_status')
                status_dict[key] = value
            break
    return status_dict
