docs: def _list_files_in_path(path, pattern="*.stan"):
      """
      indexes a directory of stan files
      returns as dictionary containing contents of files
      """
  
      results = []
      for dirname, subdirs, files in os.walk(path):
          for name in files:
              if fnmatch(name, pattern):
                  results.append(os.path.join(dirname, name))
      return(results)