Plugin Systems Development Tutorials, Guides & Insights

Metaclasses can ensure that all subclasses meet specific criteria.

class InterfaceMeta(type):
    def __new__(cls, name, bases, dct):
        if "execute" not in dct:
            raise TypeError(f"Class {name} must define an 'execute' method.")
        return super().__new__(cls, name, bases, dct)

class Base(metaclass=InterfaceMeta):
    def execute(self):
        pass  # Required method

class Derived(Base):
    def execute(self):
        print("Executing Derived")

Derived().execute()  # Works fine

# Uncommenting the following will raise an error:
# class InvalidDerived(Base):
#     pass