included

# File activemodel/lib/active_model/validations/acceptance.rb, line 32
          def included(klass)
            @lock = Mutex.new
            mod = self

            define_method(:respond_to_missing?) do |method_name, include_private = false|
              mod.define_on(klass)
              super(method_name, include_private) || mod.matches?(method_name)
            end

            define_method(:method_missing) do |method_name, *args, &block|
              mod.define_on(klass)
              if mod.matches?(method_name)
                send(method_name, *args, &block)
              else
                super(method_name, *args, &block)
              end
            end
          end