protected function validateFields(): void
    {
        $fields = $this->getArrayValue($this->joryArray, ['fld', 'fields']);

        // No fields set, that's ok. return.
        if ($fields === null) {
            return;
        }

        if (! is_array($fields)) {
            throw new JoryException('The fields parameter must be an array. (Location: '.$this->address.'fields)');
        }

        foreach ($fields as $key => $field) {
            if (! is_string($field)) {
                throw new JoryException('The fields parameter can only contain strings. (Location: '.$this->address.'fields.'.$key.')');
            }
        }
    }