ADd one more custom search service type

[gaetan....@gmail.com]

Hi ! 

I search to insert new seach service to use this service :

https://adresse.data.gouv.fr/api-doc/adresse

The document explain : 

" you will need to write your own service, to require the data to remote API"

Well, my question is : 

Where need i to insert this function ? Have i to use a custom extension to use this type of function with "setService" ?

Or, Ho can i insert new service ?

Thanks.

GB