diegosouzapw Python Engineer
Expert guidance for Python code review, quality improvement, and debugging with focus on Web API development.
Core Workflow
- Understand - Analyze current code structure and identify issues
- Diagnose - Apply relevant best practices from references
- Improve - Implement changes with proper typing and tests
- Validate - Verify improvements through testing
Code Review
When reviewing Python code, check:
- Type Safety - All functions have type hints, mypy passes
- Testing - pytest coverage for critical paths
- Clean Code - Pythonic patterns, no code smells
- Error Handling - Proper exception handling
- Documentation - Docstrings for public APIs
For detailed checklist: references/code-review.md
Debugging
Debug workflow:
- Reproduce the issue with minimal test case
- Identify error type and stack trace
- Apply targeted debugging technique
- Verify fix with test
For debugging techniques: references/debugging.md
Quality Improvement
Type Hints
Add comprehensive type annotations:
from typing import TypeVar, Generic
from collections.abc import Callable, Sequence
T = TypeVar("T")
def process_items(
items: Sequence[T],
transformer: Callable[[T], T],
) -> list[T]:
return [transformer(item) for item in items]
For complete guide: references/type-hints.md
Testing with pytest
Write meaningful tests:
import pytest
class TestUserService:
def test_create_user_with_valid_email_returns_user(
self, user_service: UserService
) -> None:
result = user_service.create("test@example.com")
assert result.email == "test@example.com"
assert result.id is not None
def test_create_user_with_invalid_email_raises_validation_error(
self, user_service: UserService
) -> None:
with pytest.raises(ValidationError, match="Invalid email"):
user_service.create("invalid-email")
For testing patterns: references/testing.md
Clean Code
Prefer:
- Composition over inheritance
- Small, focused functions (< 20 lines)
- Descriptive names over comments
- Early returns to reduce nesting
- Dataclasses/Pydantic over raw dicts
For patterns: references/clean-code.md
Web API Development
FastAPI best practices:
from fastapi import FastAPI, HTTPException, status
from pydantic import BaseModel
class UserCreate(BaseModel):
email: str
name: str
@app.post("/users", status_code=status.HTTP_201_CREATED)
async def create_user(user: UserCreate) -> User:
if await user_exists(user.email):
raise HTTPException(
status_code=status.HTTP_409_CONFLICT,
detail="User already exists"
)
return await create_user_in_db(user)
For FastAPI patterns: references/fastapi.md
References
- references/code-review.md - Code review checklist
- references/clean-code.md - Pythonic patterns
- references/testing.md - pytest best practices
- references/type-hints.md - Type annotation guide
- references/fastapi.md - FastAPI development
- references/debugging.md - Debugging techniques