How can I convert Python API calls to Javascript arrays to make a Flask app look nicer?

Can Python API calls be converted to Javascript arrays so Javascript can be used to make it look nicer when rendered in a Flask app? I am working on a project but my friend who is a python programmer wants to use Python to make the API call, problem is I am a JavaScript / Web programmer, so I haven’t the first clue how to convert the Python API response into a Python Array, then somehow pass that data to a JavaScript Array so I can work with the data and make it look nicer on the website project we are building.

I can do the API call with fetch() way easier since we are developing a web application, but he is insisting on Python because we’re trying to use Flask.