    # File lib/spec/mocks/proxy.rb, line 39
          def add_message_expectation(expected_from, sym, opts={}, &block)
            __add sym
            warn_if_nil_class sym
            if existing_stub = @stubs.detect {|s| s.sym == sym }
              expectation = existing_stub.build_child(expected_from, block_given?? block : nil, 1, opts)
            else
              expectation = MessageExpectation.new(@error_generator, @expectation_ordering, expected_from, sym, block_given? ? block : nil, 1, opts)
            end
            @expectations << expectation
            @expectations.last
          end