# File lib/aws/s3/acl_object.rb, line 140
        def object_input_validator(klass, base_name, method_name, cast)
          input_validator(method_name) do |value, context|
            if value.kind_of?(cast)
              klass.new(value).validate!
            else
              raise ArgumentError.new("expected #{base_name} object or hash"+context) unless
                value.nil? or value.kind_of? klass
            end
          end
        end