How dose spark streaming program call python file

I am trying to build a real-time system with spark （written with scala）, but here are some algorithm file written in python. How can i call the algorithm file ？ Any idea how to let it work？

***UNCHECKED*** How dose spark streaming program （written with scala）call python file

I am trying to build a real-time system with spark （written with scala）, but here are some algorithm file written in python. How can i call the algorithm file ？ Any idea how to let it work？