docs: def get_inner_text(text, entities):
      """
      Gets the inner text that's surrounded by the given entities.
      For instance: text = 'hey!', entity = MessageEntityBold(2, 2) -> 'y!'.
  
      :param text:     the original text.
      :param entities: the entity or entities that must be matched.
      :return: a single result or a list of the text surrounded by the entities.
      """
      text = add_surrogate(text)
      result = []
      for e in entities:
          start = e.offset
          end = e.offset + e.length
          result.append(del_surrogate(text[start:end]))
  
      return result