Currently there are two versions of blurb on PyPI:

• 1.0 can be installed on 3.5, but doesn't work since uses 3.6 syntax (f-strings).
• 1.0.1 uses 3.5 syntax, bat requires Python >= 3.6.

As result when you install blurb on 3.5, version 1.0 is installed, which doesn't work.