docs: def tail_field(field):
      """
      RETURN THE FIRST STEP IN PATH, ALONG WITH THE REMAINING TAIL
      """
      if field == "." or field==None:
          return ".", "."
      elif "." in field:
          if "\\." in field:
              return tuple(k.replace("\a", ".") for k in field.replace("\\.", "\a").split(".", 1))
          else:
              return field.split(".", 1)
      else:
          return field, "."