Conventions

Package-wide conventions I prefer.

Naming 

Ctx Managers: {}_ctx.
Enums: {}_e.
Flags: {}_f.
Hooks: {}_h.
Interfaces: {}_i.
Loggers: {}_l.
Mixins: {}_m.
Protocols: {}_p.
Slot-based Data: {}_d.
Specs: {}_c.
Structs: {}_s.
util not utils.

Package Structure 

Top Level Package Structure. Note the in-tree rst documentation.

<package>/
├── __init__.py
├── py.typed
├── index.rst
├── _abstract/
├── _docs/
   └── conf.py
   └── _static/
   └── _templates/
├── <module>/

Module Structure 

Module structure is similar to top level package structure. Interfaces, protocols, simple data structures etc go into the _interface.py file.

<module>/
├── __init__.py
├── _interface_.py
├── index.rst
└── __tests/
   └── __init__.py
   └── test_{class}.py
└── __examples/