def instances_of(class_name, options = {})
      unless class_name.is_a?(Class)
        # class_name is actually an instance of the class to search for, not the class itself.
        class_name = class_name.class
      end
      @_componentable_container.select do |name, component|
        component.is_a?(class_name)
      end.keys
    end
def instances_of(class_name, options = {})
      unless class_name.is_a?(Class)
        # class_name is actually an instance of the class to search for, not the class itself.
        class_name = class_name.class
      end
      @_componentable_container.select do |name, component|
        component.is_a?(class_name)
      end.keys
    end
Locates all names whose object is a :class_name object.
 @param class_name [Class, Instance of Class] Class to search componentable container for. This can either be the class name, or can be an instance of the class to search for.
 @return [Array <Strings>] An array listing all of the names in the componentable container which are a :class_name.