python-pro Checked
Installation
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Install the "python-pro" skill by following the instructions at https://skill123.me/install/python-pro.
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curl -fsSL https://skill123.me/install/python-pro.sh | bash
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⬇ Download v1.0.0 · 19 KBNot live-tested yet — this skill is rated on static analysis only.
About this skill
Use when building Python 3.11+ applications requiring type safety, async programming, or robust error handling. Generates type-annotated Python code, configures mypy in strict mode, writes pytest test suites with fixtures and mocking, and validates code with black and ruff. Invoke for type hints, async/await patterns, dataclasses, dependency injection, logging configuration, and structured error handling.
Python Pro
Modern Python 3.11+ specialist focused on type-safe, async-first, production-ready code.
Documentation
Use when building Python 3.11+ applications requiring type safety, async programming, or robust error handling. Generates type-annotated Python code, configures mypy in strict mode, writes pytest test suites with fixtures and mocking, and validates code with black and ruff. Invoke for type hints, async/await patterns, dataclasses, dependency injection, logging configuration, and structured error handling.
Python Pro
Modern Python 3.11+ specialist focused on type-safe, async-first, production-ready code.
When to Use This Skill
- Writing type-safe Python with complete type coverage
- Implementing async/await patterns for I/O operations
- Setting up pytest test suites with fixtures and mocking
- Creating Pythonic code with comprehensions, generators, context managers
- Building packages with Poetry and proper project structure
- Performance optimization and profiling
Core Workflow
1. **Analyze codebase** — Review structure, dependencies, type coverage, test suite
2. **Design interfaces** — Define protocols, dataclasses, type aliases
3. **Implement** — Write Pythonic code with full type hints and error handling
4. **Test** — Create comprehensive pytest suite with >90% coverage
5. **Validate** — Run mypy --strict, black, ruff
- If mypy fails: fix type errors reported and re-run before proceeding
- If tests fail: debug assertions, update fixtures, and iterate until green
- If ruff/black reports issues: apply auto-fixes, then re-validate
Reference Guide
Load detailed guidance based on context:
| Topic | Reference | Load When |
|-------|-----------|-----------|
| Type System | references/type-system.md | Type hints, mypy, generics, Protocol |
| Async Patterns | references/async-patterns.md | async/await, asyncio, task groups |
| Standard Library | references/standard-library.md | pathlib, dataclasses, functools, itertools |
| Testing | references/testing.md | pytest, fixtures, mocking, parametrize |
| Packaging | references/packaging.md | poetry, pip, pyproject.toml, distribution |
Constraints
### MUST DO
- Type hints for all function signatures and class attributes
- PEP 8 compliance with black formatting
- Comprehensive docstrings (Google style)
- Test coverage exceeding 90% with pytest
- Use
X | Noneinstead ofOptional[X](Python 3.10+) - Async/await for I/O-bound operations
- Dataclasses over manual __init__ methods
- Context managers for resource handling
### MUST NOT DO
- Skip type annotations on public APIs
- Use mutable default arguments
- Mix sync and async code improperly
- Ignore mypy errors in strict mode
- Use bare except clauses
- Hardcode secrets or configuration
- Use deprecated stdlib modules (use pathlib not os.path)
Code Examples
### Type-annotated function with error handling
from pathlib import Path
def read_config(path: Path) -> dict[str, str]:
"""Read configuration from a file.
Args:
path: Path to the configuration file.
View full documentation
Returns:
Parsed key-value configuration entries.
Raises:
FileNotFoundError: If the config file does not exist.
ValueError: If a line cannot be parsed.
"""
config: dict[str, str] = {}
with path.open() as f:
for line in f:
key, _, value = line.partition("=")
if not key.strip():
raise ValueError(f"Invalid config line: {line!r}")
config[key.strip()] = value.strip()
return config
### Dataclass with validation
from dataclasses import dataclass, field
@dataclass
class AppConfig:
host: str
port: int
debug: bool = False
allowed_origins: list[str] = field(default_factory=list)
def __post_init__(self) -> None:
if not (1 <= self.port <= 65535):
raise ValueError(f"Invalid port: {self.port}")
### Async pattern
import asyncio
import httpx
async def fetch_all(urls: list[str]) -> list[bytes]:
"""Fetch multiple URLs concurrently."""
async with httpx.AsyncClient() as client:
tasks = [client.get(url) for url in urls]
responses = await asyncio.gather(*tasks)
return [r.content for r in responses]
### pytest fixture and parametrize
import pytest
from pathlib import Path
@pytest.fixture
def config_file(tmp_path: Path) -> Path:
cfg = tmp_path / "config.txt"
cfg.write_text("host=localhost\nport=8080\n")
return cfg
@pytest.mark.parametrize("port,valid", [(8080, True), (0, False), (99999, False)])
def test_app_config_port_validation(port: int, valid: bool) -> None:
if valid:
AppConfig(host="localhost", port=port)
else:
with pytest.raises(ValueError):
AppConfig(host="localhost", port=port)
### mypy strict configuration (pyproject.toml)
[tool.mypy]
python_version = "3.11"
strict = true
warn_return_any = true
warn_unused_configs = true
disallow_untyped_defs = true
Clean `mypy --strict` output looks like:
Success: no issues found in 12 source files
Any reported error (e.g., `error: Function is missing a return type annotation`) must be resolved before the implementation is considered complete.
## Output Templates
When implementing Python features, provide:
1. Module file with complete type hints
2. Test file with pytest fixtures
3. Type checking confirmation (mypy --strict passes)
4. Brief explanation of Pythonic patterns used
## Knowledge Reference
Python 3.11+, typing module, mypy, pytest, black, ruff, dataclasses, async/await, asyncio, pathlib, functools, itertools, Poetry, Pydantic, contextlib, collections.abc, Protocol
[Documentation](https://jeffallan.github.io/claude-skills/skills/language/python-pro/)
Score breakdown
Assessment methodology
Version history
Imported from Jeffallan/claude-skills@main