code: def _format_newlines(prefix, formatted_node, options):
      
      replacement = u''.join([
          options.NEWLINE,
          u'\n',
          prefix])
      return formatted_node.replace(u'\n', replacement)
docs: Convert newlines into U+23EC characters, followed by an actual newline and
      then a tree prefix so as to position the remaining text under the previous
      line.