How to reference a field value in mosaic table to use in Python RFT

Hi,
I made a simple Python RFT chained with another RFT template. I use a Rasterize Feature to access a value inside a feature table. Then I am able to apply my python RFT to a mosaic. But It is not optimal for me.
I would like to directly use this numeric value stored in a field of my mosaic (this value can change from one raster to another inside the mosaic).
I made lot of test but unsuccessful.
Does someone has an idea on how to do that ?

thanks for your help.

Start by reproducing the chained Python RFT using Rasterize Feature and the mosaic field value described in the issue. Review how mosaic attributes are exposed to raster functions, then verify that the numeric value can be passed directly and varies correctly for each raster.

Written by the indexing model from the issue text.