def to_xml(options = {})
      xml = options[:builder] ||= Builder::XmlMarkup.new
      xml.instruct! unless options[:skip_instruct]
      xml.osm do
        xml.changeset(attributes) do
          tags.each do |k,v|
            xml.tag(:k => k, :v => v)
          end unless tags.empty?
        end
      end
    end
def to_xml(options = {})
      xml = options[:builder] ||= Builder::XmlMarkup.new
      xml.instruct! unless options[:skip_instruct]
      xml.osm do
        xml.changeset(attributes) do
          tags.each do |k,v|
            xml.tag(:k => k, :v => v)
          end unless tags.empty?
        end
      end
    end
Renders the object as an xml representation compatible to the OSM API
 @return [String] XML