ask-python-refactor

<critical_constraints> ❌ NO refactoring without tests first ❌ NO single-letter variables (n, x) → use descriptive names ❌ NO functions >20 lines → extract smaller functions ✅ MUST run tests after every change ✅ MUST commit frequently for easy rollback </critical_constraints>

<code_smells>

• Duplicated code → extract to shared function
• Long parameter lists → group into dataclass
• Deep nesting → use early returns/guard clauses
• Magic numbers → replace with named constants </code_smells>

Type Hints

def get_user(user_id: int) -> Optional[User]:
    return db.find(user_id)