def remove_sprocket(name)
      if sprocket = get_sprocket(name)
        sprockets.delete sprocket
        set_sprocket(name, nil)
      end
    end
def remove_sprocket(name)
      if sprocket = get_sprocket(name)
        sprockets.delete sprocket
        set_sprocket(name, nil)
      end
    end
Removes the sprocket with the given name. This is useful if
 you don't need one of the default Sprockets.