Classes should be open for extension but closed for modification.
The .7z extension indicates a compressed archive created with . In the context of a "PHP Guide," this archive likely contains: SOLID Principles in Laravel & PHP: A Practical Guide php-guide.7z
Instead of one massive WorkerInterface , create smaller interfaces like WorkableInterface and SleepableInterface so a robot class isn't forced to implement a sleep() method. D: Dependency Inversion Principle (DIP) Classes should be open for extension but closed