# File lib/rspec/mocks/method_double.rb, line 208
      def add_expectation(error_generator, expectation_ordering, expected_from, opts, &implementation)
        configure_method
        expectation = MessageExpectation.new(error_generator, expectation_ordering,
                                             expected_from, self, 1, opts, &implementation)
        expectations << expectation
        expectation
      end