nodes: 0, module; 1, function_definition; 2, function_name:echo_headers; 3, parameters; 4, block; 5, identifier:headers; 6, default_parameter; 7, expression_statement; 8, for_statement; 9, expression_statement; 10, identifier:file; 11, None; 12, comment:"""Echo headers, sorted."""; 13, pattern_list; 14, call; 15, block; 16, call; 17, identifier:k; 18, identifier:v; 19, identifier:sorted; 20, argument_list; 21, expression_statement; 22, attribute; 23, argument_list; 24, call; 25, call; 26, identifier:click; 27, identifier:echo; 28, keyword_argument; 29, attribute; 30, argument_list; 31, attribute; 32, argument_list; 33, identifier:file; 34, identifier:file; 35, identifier:headers; 36, identifier:items; 37, identifier:click; 38, identifier:echo; 39, call; 40, keyword_argument; 41, attribute; 42, argument_list; 43, identifier:file; 44, identifier:file; 45, string:"{0}: {1}"; 46, identifier:format; 47, call; 48, identifier:v; 49, attribute; 50, argument_list; 51, identifier:k; 52, identifier:title
code: def echo_headers(headers, file=None):
      """Echo headers, sorted."""
      for k, v in sorted(headers.items()):
          click.echo("{0}: {1}".format(k.title(), v), file=file)
      click.echo(file=file)