Use standard docstring format
Python docstrings themselves don't require any specific standardized formatting, but the community has settled mostly around two different standards:
Prefect is currently using neither, but is closer to google's standard. Standards are nice - they make it easier for external contributors to start working (they're already used to the standard from other projects), and play nicely with community tools (sphinx can generate nice docs from both numpy and google standard docstrings). If you create your own standard, every contributor has to learn something new and undocumented.
I personally prefer the NumPy standard, but that's because I come from projects that use that formatting and am more used to it (I suspect many contributors in Prefect's space will be more familiar with that standard as well, since it's more common in datascience-y libraries). Either is fine.