# File lib/facet/object/supers.rb, line 16
  def supers(klass=self.class.superclass)
    raise ArgumentError if ! self.class.ancestors.include?(klass)
    Functor.new do |meth, *args|  # &blk|
      klass.instance_method(meth).bind(self).call(*args) # ,&blk)
    end
  end