Support Python 3 Templates
Templates only support Python 2.7 - https://cloud.google.com/deployment-manager/docs/configuration/templates/create-basic-template#template_syntax
Python 3 is the modern version of python and 2.7 will soon stop being maintained - https://pythonclock.org/.
Apparently Python v3 support is still not here. So what are we to do with 2.7 End of Life approaching?
Support for Python v3 is planned for an upcoming release. This may not be broadly available until early 2019.