Nette\PhpGenerator\Parameter::setOptional PHP Method

    public function setOptional($state = TRUE)
    {
        $this->optional = (bool) $state;
        return $this;
    }

 /** @return Parameter */
 public function addParameter($name, $defaultValue = NULL)
 {
     $param = new Parameter();
     if (func_num_args() > 1) {
         $param->setOptional(TRUE)->setDefaultValue($defaultValue);
     }
     return $this->parameters[$name] = $param->setName($name);
 }