I have recently discovered you can use R within Tableau, to return bool, int, long etc. This happens by the following:
// Should say "Starting RServe..."
// For Tableau under 'Help' > 'Settings and Performance' > 'Manage R Connections'
// Server: 127.0.0.1 and Port:6311
// Make sure that 'RStudio' with 'RServer' is installed and running prior to Tableau connection
There isn't a Script() call for languages other than R as of Tableau 8.2.
You could try using R as a middleman to invoke Python functions via the rPython or RSPython packages. No idea how performant it would be, but might be worth the hassle if you have a significant Python library that isn't available in R.