def to_xml(options = {})
      xml = options[:builder] ||= Builder::XmlMarkup.new
      xml.instruct! unless options[:skip_instruct]
      each do |key, value|
        # Remove leading and trailing whitespace from tag values
        xml.tag(:k => key, :v => coder.decode(value.strip)) unless value.blank?
      end unless empty?
    end
def to_xml(options = {})
      xml = options[:builder] ||= Builder::XmlMarkup.new
      xml.instruct! unless options[:skip_instruct]
      each do |key, value|
        # Remove leading and trailing whitespace from tag values
        xml.tag(:k => key, :v => coder.decode(value.strip)) unless value.blank?
      end unless empty?
    end
Return XML for these tags. This method uses the Builder library.
 The only parameter ist the builder object.