code: def remove_read_more_sep(self, raw_content):
          
          if self._read_more_exp is None:
              return raw_content
  
          sp = self._read_more_exp.split(raw_content, maxsplit=1)
          if len(sp) == 2 and sp[0]:
              result = '\n\n'.join((sp[0].rstrip(), sp[1].lstrip()))
          else:
              result = raw_content
          return result
docs: Removes the first read_more_sep that occurs in raw_content.
          Subclasses should call this method to preprocess raw_content.