Python Coding Standards (PEP 8)

When reviewing or generating Python code, follow these rules:

File Naming

• Source files: Use snake_case (e.g., user_service.py , api_client.py )

• Package directories: Use snake_case (e.g., data_processing/ , utils/ )

• Test files: Use test_ prefix (e.g., test_user_service.py )

• Config files: Use snake_case (e.g., config_settings.py )

Variable Naming

• Variables: snake_case (e.g., user_name , is_active , total_count )

• Constants: UPPER_SNAKE_CASE (e.g., MAX_RETRIES , API_BASE_URL )

• Boolean variables: Prefix with is_ , has_ , can_ , should_ (e.g., is_loading , has_error )

• Protected variables: Single underscore prefix (e.g., _internal_data )

• Private variables: Double underscore prefix (e.g., __private_data )

Function Naming

• Functions: snake_case (e.g., calculate_total() , fetch_user_data() )

• Private functions: Prefix with underscore (e.g., _validate_input() , _process_data() )

• Dunder methods: Double underscores (e.g., init , str , repr )

Class Naming

• Classes: PascalCase (e.g., UserService , DataProcessor , ApiClient )

• Exception classes: PascalCase with Error or Exception suffix (e.g., ValidationError )

• Abstract classes: PascalCase, optionally prefix with Base or Abstract (e.g., BaseHandler )

Method Naming

• Instance methods: snake_case (e.g., get_user() , process_data() )

• Class methods: snake_case with @classmethod decorator

• Static methods: snake_case with @staticmethod decorator

• Properties: snake_case with @property decorator

Module Organization

• Imports at the top: standard library, third-party, local imports (separated by blank lines)

• Module-level dunder names after imports (all , version )

• One class per file for large classes; multiple related classes okay for small ones

• Use all to define public API