Howtos for The Rest of Us

← Skills

Python Standards

Version

• Target Python 3.11+

Style (PEP 8)

• 4-space indent, 88 char line limit (Black default)
• snake_case functions/vars, UPPER_SNAKE_CASE constants, PascalCase classes
• Type hints on all function signatures

Imports

• Standard lib -> third-party -> local, blank line between groups
• Absolute imports preferred

Types

• mypy --strict in CI. dataclass over dicts for structured data
• Enum or StrEnum for fixed sets. T | None in 3.10+

Errors

• Catch specific types, never bare except:. contextlib.suppress for ignored errors
• Log with logging.getLogger(__name__), never print

Dependencies

• pip freeze > requirements.txt or Poetry/pyproject.toml
• Pin major versions, ~= for compatible releases

Testing

• pytest with pytest-cov. Tests in tests/ mirroring src/
• Fixtures for setup, parametrize for data-driven tests
• Mock external IO, test business logic directly

CLI

• argparse or click for CLI tools. --verbose/-v and --quiet/-q