Access file dynamically in python

hello all,i need a small help ,please let me know,which function in python access the file path dynamically,suppose i will select a csv file from postman then in the python script i need a function which access the path in varible.
i have a function in node which is var files = req.file[“path”];
like this can u pls let me know what funtion we have in python or what is that library?