I created an app on the DigitalOcean App Platform with a requirements.txt and a Procfile - causing it to detect a Python application and build the app with their Python buildpack.
Here are some details of the resulting environment, from running commands using the DigitalOcean web terminal.
$ uname -a
Linux digital-ocean-app-9c6bd5794-kt9h8 4.4.0 #1 SMP Sun Jan 10 15:06:54 PST 2016 x86_64 x86_64 x86_64 GNU/Linux
$ cat /etc/issue