append_features

# File lib/rss/atom.rb, line 20
      def self.append_features(klass)
        super
        klass.install_must_call_validator("atom", URI)
        [
         ["lang", :xml],
         ["base", :xml],
        ].each do |name, uri, required|
          klass.install_get_attribute(name, uri, required, [nil, :inherit])
        end
        klass.class_eval do
          class << self
            def required_uri
              URI
            end

            def need_parent?
              true
            end
          end
        end
      end