How to pass variable value to a python file from robotframework file?

Python file

sysman_auth = (username, password)

Robot file

*** Variables ***
${uname}     testuser
${password}   testpassword

How do I pass testuser and testpassword from sample.robot file to file?

If by ‘passing it to .py’ you mean using one of the functions in the .py file as a keyword, there are 2 ways to do that which I elaborated on this article - Extend robotframework using the robotframework python lib core | by Eldad Uzman | Medium

If instead you mean running the .py file as a script with arguments then you need to execute it in a different process and you can do that with robot frameworks operating system library - OperatingSystem - Documentation