https://github.com/bakaphp/phalcon-elasticsearch/blob/97c981644bde6b7f31c6623469b0d879d57cfce1/src/IndexBuilderStructure.php#L127-L132 --- ###### This issue was generated by [todo](https://todo.jasonet.co) based on a `TODO` comment in 97c981644bde6b7f31c6623469b0d879d57cfce1 when #8 was merged. cc @bakaphp.