Singleton Design Pattern in Python

Ensure a class only has one instance, and provide a global point of
access to it.

class Singleton(type):
    Define an Instance operation that lets clients access its unique

    def __init__(cls, name, bases, attrs, **kwargs):
        super().__init__(name, bases, attrs)
        cls._instance = None

    def __call__(cls, *args, **kwargs):
        if cls._instance is None:
            cls._instance = super().__call__(*args, **kwargs)
        return cls._instance

class MyClass(metaclass=Singleton):
    Example class.


def main():
    m1 = MyClass()
    m2 = MyClass()
    assert m1 is m2

if __name__ == "__main__":

Code examples