I am working on a system at present where the data scientist has done the calculations in an R script. We agreed upon an input data.frame and an output csv as our 'interface'.

I added the SQL query to the top of the R script to generate the input data.frame and my Python code reads the output CSV to do subsequent processing and storage into Django models.

I use a subprocess running Rscript to run the script.

It's not elegant but it is simple. This part of the system only has to run daily so efficiency isn't a big deal.