def add(*items)
      notify_will_change! if items.count > 0
      items.flatten.parse_objects.each do |item|
        collection.push(item) if item.is_a?(Parse::Pointer)
      end
      @collection
    end
def add(*items)
      notify_will_change! if items.count > 0
      items.flatten.parse_objects.each do |item|
        collection.push(item) if item.is_a?(Parse::Pointer)
      end
      @collection
    end
Add Parse::Objects to the collection.
 @overload add(parse_object)
  Add a Parse::Object or Parse::Pointer to this collection.
  @param parse_object [Parse::Object,Parse::Pointer] the object to add
 @overload add(parse_objects)
  Add an array of Parse::Objects or Parse::Pointers to this collection.
  @param parse_objects [Array<Parse::Object,Parse::Pointer>] the array to append.
 @return [Array<Parse::Object>] the collection