def each_output_coupling_reverse(port)
      return enum_for(:each_output_coupling_reverse) unless block_given?
      _output_couplings.each do |src, ary|
        ary.each { |dst| yield(src,dst) if dst == port }
      end
    end
def each_output_coupling_reverse(port)
      return enum_for(:each_output_coupling_reverse) unless block_given?
      _output_couplings.each do |src, ary|
        ary.each { |dst| yield(src,dst) if dst == port }
      end
    end
TODO doc