Assert\Assertion::null PHP Method

    public static function null($value, $message = null, $propertyPath = null)
    {
        if ($value !== null) {
            $message = sprintf($message ?: 'Value "%s" is not null, but null value was expected.', static::stringify($value));
            throw static::createException($value, $message, static::VALUE_NOT_NULL, $propertyPath);
        }
        return true;
    }