public function field($field, $prefix = null)
    {
        if (is_array($field)) {
            $field = new Field($field);
        }

        if (! $field instanceof FieldInterface) {
            throw new Exception('Field must implement interface '.FieldInterface::class.' or be an array.');
        }

        $formField = $this->getRegistrar()->resolve($field);

        if ($prefix) {
            $formField->setPrefix($prefix);
        }

        return $formField;
    }