code: def split_flanks(self, _, result):
          
          if not result.strip():
              self.left, self.right = "", ""
              return result
  
          match = self.flank_re.match(result)
          assert match, "This regexp should always match"
          self.left, self.right = match.group(1), match.group(3)
          return match.group(2)
docs: Return `result` without flanking whitespace.