Tutorials Programming Tutorials, Guides & Best Practices

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

def generate_numbers(start, end):
    for i in range(start, end):
        yield i

def filter_even(numbers):
    for num in numbers:
        if num % 2 == 0:
            yield num

def square(numbers):
    for num in numbers:
        yield num ** 2

# Chaining
numbers = generate_numbers(1, 10)
even_numbers = filter_even(numbers)
squared_numbers = square(even_numbers)

print(list(squared_numbers))  # Output: [4, 16, 36, 64]

The yield from statement allows a generator to delegate part of its operations to another generator.