def remove_child_object(identifier)
      found_child = children.find {|child| child.identifier == identifier }
      @properties['children'].delete identifier
      save!
      found_child
    end
def remove_child_object(identifier)
      found_child = children.find {|child| child.identifier == identifier }
      @properties['children'].delete identifier
      save!
      found_child
    end
This method is used internally to remove a child object from this and the
 registry.

 @param [String] identifier of the child object to be removed.
 @return [Resource] the removed child resource