code: public function overrideAt($index, $token)
      {
          @trigger_error(__METHOD__.' is deprecated and will be removed in 3.0, use offsetSet instead.', E_USER_DEPRECATED);
          self::$isLegacyMode = true;
  
          $this[$index]->override($token);
          $this->registerFoundToken($token);
      }
docs: Override token at given index and register it.
  
  @param int                $index
  @param array|string|Token $token token prototype
  
  @deprecated since 2.4, use offsetSet instead