def write_to_file(path, indent: -1, pretty: false, options: { mapping: :_default })
      doc = REXML::Document.new
      doc << REXML::XMLDecl.new
      doc.elements[1] = save_to_xml(options)
      File.open(path, 'w') do |f|
        return doc.write(f, indent) unless pretty
        formatter = REXML::Formatters::Pretty.new
        formatter.compact = true
        formatter.write(doc, f)
      end
    end
def write_to_file(path, indent: -1, pretty: false, options: { mapping: :_default })
      doc = REXML::Document.new
      doc << REXML::XMLDecl.new
      doc.elements[1] = save_to_xml(options)
      File.open(path, 'w') do |f|
        return doc.write(f, indent) unless pretty
        formatter = REXML::Formatters::Pretty.new
        formatter.compact = true
        formatter.write(doc, f)
      end
    end
Writes this mapped object to the specified file, as an XML document (including declaration).

 @param path [String] The path of the file to write to
 @param indent [Integer] The indentation level. Defaults to -1 (no indenting). Note
   that this parameter will be ignored if `pretty` is present.
 @param pretty [Boolean] Whether to pretty-print the output. Defaults to `false`. Note
   that this option overrides `indent`.
 @param options [Hash] the options to be passed to
   [XML::Mapping#save_to_xml](http://multi-io.github.io/xml-mapping/XML/Mapping.html#method-i-save_to_xml)