code: func HasChildren(rp *object.ResourcePool) (bool, error) {
  	props, err := Properties(rp)
  	if err != nil {
  		return false, err
  	}
  	if len(props.Vm) > 0 || len(props.ResourcePool) > 0 {
  		return true, nil
  	}
  	return false, nil
  }
docs: // HasChildren checks to see if a resource pool has any child items (virtual
  // machines, vApps, or resource pools) and returns true if that is the case.
  // This is useful when checking to see if a resource pool is safe to delete.
  // Destroying a resource pool in vSphere destroys *all* children if at all
  // possible, so extra verification is necessary to prevent accidental removal.