# File lib/rspec/mocks/any_instance/message_chains.rb, line 36
        def playback!(instance, method_name)
          self[method_name].each do |chain|
            @instance_with_expectation = instance if instance.is_a?(ExpectationChain) && !@instance_with_expectation
            if instance.is_a?(ExpectationChain) && !@instance_with_expectation.equal?(instance)
              raise RSpec::Mocks::MockExpectationError, "Exactly one instance should have received the following message(s) but didn't: #{unfulfilled_expectations.sort.join(', ')}"
            end
            chain.playback!(instance)
          end
        end