docs: def of_text(self, text, encoding="utf-8"):
          """
          Use default hash method to return hash value of a piece of string
          default setting use 'utf-8' encoding.
  
          :type text: text_type
          :param text: a text object
          """
          m = self.hash_algo()
          m.update(text.encode(encoding))
          return self.digest(m)