OpenAPI-Generator Python Client Instructions Examples
OK fine, found useful information on READme.md generated by OpenAPI-generator itself
and tried pdoc to get html document of my OpenAPI-generator generated client Module
Moreover on stackoverflow How to generate API Documentation using openapi-generator? you can find how OpenApi Generator can do generation of html documentation from your yaml or json definition of your API.
For openAPI json api specification I found RapiPDF too : Web Component to generate PDF from OpenAPI Spec (json yml file).