Python

Purpose

Python-specific conventions for readability, correctness, maintainability.

Core Principles

1. •Idiomatic Python style & stdlib practices
2. •Explicitness > cleverness
3. •Typing & tests reduce regressions

Rules

Style

• •PEP 8 naming & formatting
• •Use black or project formatter if specified
• •Small, focused functions

Types & Errors

• •Type hints for public APIs & complex functions
• •Exceptions for exceptional conditions, not control flow
• •Prefer pathlib over string paths

Structure

• •Group imports: stdlib → third-party → local
• •Avoid mutable default arguments

Examples

✅ "Use pathlib.Path & type hints for file utilities" ❌ "Use global state & implicit side effects"

Edge Cases

• •Performance hotspots: measure before optimizing
• •Legacy code: prioritize consistency w/ existing patterns

See COMMON.md.

Refs: PEP 8, PEP 484, pathlib (2026-01-26)