You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: generator.rb
    path of file: ./repos/oga/lib/oga/xml
    
    the code of the file until where you have to start completion: module Oga
  module XML
    # Class for generating XML as a String ba
    
      def on_xml_declaration(node, output)
        output << '<?xml'

        [:version, :encoding, :standalone].each do |getter|
          value = node.send(getter)

          output << %Q{ #{getter}="#{value}"} if value
        end

        output << ' ?>'
      end