# File lib/moqueue/matchers.rb, line 37
      def matches?(queue_or_exchange)
        if queue_or_exchange.respond_to?(:received_ack_for_message?)
          @queue_or_exchange = queue_or_exchange
          @queue_or_exchange.received_ack_for_message?(@msg_expecting_ack)
        else
          raise NoMethodError,
          "Grrr. you can't use ``should have_received_ack_for'' on #{queue_or_exchange.inspect} " +
          "because it doesn't respond_to :received_ack_for_message?"
        end
      end