How to add a custom filter for use in a cookiecutter template?

Question

how can I add a custom filter to be used in a jinja template used by cookiecutter?

I tried adding using a pre_gen_project hook, it's called, but I can't find a way to make my python functions visible as jinja filters (or function) inside the templates.

Incertitude

Have you read the jinja2 docs? – Cervin

Yes, using the filter decorators didn't work nor adding to a new enviroment's filter dict. I must be missing something. – Creolized

you should show your filter code and how you call your filter in jinja2 env – Azelea

This is possible using local extensions. See cookiecutter.readthedocs.io/en/latest/advanced/… – Shrunk