public function getIndentationColumnIndex()
    {
        if (null === $this->indentationColumnIndex) {
            $field = $this->getGenerator()->getFromYaml('builders.nested_list.indentation.field');
            if (!$field) {
                return $this->indentationColumnIndex = 0;
            }

            $this->indentationColumnIndex = array_search($field, array_keys($this->getColumns()));
        }

        return $this->indentationColumnIndex;
    }