code: public function addRules($rules, $append = true)
      {
          if (!$this->enablePrettyUrl) {
              return;
          }
          $rules = $this->buildRules($rules);
          if ($append) {
              $this->rules = array_merge($this->rules, $rules);
          } else {
              $this->rules = array_merge($rules, $this->rules);
          }
      }
docs: Adds additional URL rules.
  
  This method will call [[buildRules()]] to parse the given rule declarations and then append or insert
  them to the existing [[rules]].
  
  Note that if [[enablePrettyUrl]] is `false`, this method will do nothing.
  
  @param array $rules the new rules to be added. Each array element represents a single rule declaration.
  Please refer to [[rules]] for the acceptable rule format.
  @param bool $append whether to add the new rules by appending them to the end of the existing rules.