public function insertFields($fields, $index)
    {
        if (!$fields instanceof NamedBuilder && !is_array($fields)) {
            return;
        }

        // If a singular field config, put into an array of fields
        if ($fields instanceof NamedBuilder) {
            $fields = [$fields];
        }


        foreach ($fields as $i => $field) {
            if ($this->validateField($field)) {
                array_splice($this->fields, $index + $i, 0, [$field]);
            }
        }
    }