Nelmio\Alice\Generator\Resolver\Value\Chainable\OptionalValueResolver::canResolve PHP Метод

    public function canResolve(ValueInterface $value) : bool
    {
        return $value instanceof OptionalValue;
    }

 public function testCanResolveOptionalValues()
 {
     $resolver = new OptionalValueResolver();
     $this->assertTrue($resolver->canResolve(new OptionalValue('', '')));
     $this->assertFalse($resolver->canResolve(new FakeValue()));
 }