This change fixes up a bunch of warnings that are showing up:

Replaced sre_constants.error with re.error
Add action placements where appropriate.
Replace datetime.utcnow() with datetime.now(timezone.utc)
Fixed datagrid __init__ methods to match args-vs-kwargs from the

  base class.
Added maxsplit to an re.split() call that's then destructured into

  two variables.
Changed the import path for cryptography's CFB8 cipher.
Removed an unused return value from a couple test_* methods.

Ran unit tests.