code: def is_purrlog(path):
          
          if not os.path.isdir(path):
              return False
          if list(filter(os.path.isdir, glob.glob(
                  os.path.join(path, "entry-[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]-[0-9][0-9][0-9][0-9][0-9][0-9]")))):
              return True
          return os.path.exists(os.path.join(path, "dirconfig"))
docs: Checks if path refers to a valid purrlog.
          Path must exist, and must contain either at least one directory called entry-YYYYMMDD-HHMMSS, or the file "dirconfig"