protected function validateDifferent($value, string $parameter, array $args = [], array $rules = null, array $context = null): ?string
    {
        if (count($args) == 0) {
            throw new ValidatorConfigException("Validator 'different' must have argument in validator list for parameter {$parameter}");
        }

        $differentAsField = trim($args[0]);

        if (strlen($differentAsField) == 0) {
            throw new ValidatorConfigException("Validator 'different' must have non-empty argument; parameter={$parameter}");
        }

	    $present = $this->validatePresent($value, $differentAsField, [], $rules, $context);
        if ($present !== null) {
            return $present;
        }

        //$value = $this->getValue($parameter);

        if ($value === null) {
            return null;
        }

        if (!is_scalar($value)) {
            return Message::getMessage(Message::PRIMITIVE, [
                'param' => $parameter
            ]);
        }

        $differentAsValue = $context[$differentAsField] ?? null;

        if (!is_scalar($differentAsValue)) {
            return Message::getMessage(Message::PRIMITIVE, [
                'param' => $differentAsField
            ]);
        }

        if ($value == $differentAsValue) {
            return Message::getMessage(Message::DIFFERENT, [
                'param' => $parameter,
                'value' => $value,
                'otherField' => $differentAsField,
                'otherValue' => $differentAsValue
            ]);
        }

        return null;
    }