class Single():
_instance = None
def __new__(cls, *args, **kwargs):
if not cls._instance:
cls._instance = object.__new__(cls)
return cls._instance
class A(Single):
def __init__(self, x):
self.x = x
def __str__(self):
return str(self.x)
if __name__ == '__main__':
my_class1 = A(1)
my_class2 = A(2)
my_class3 = A(3)
my_class4 = A(4)
print(my_class1,my_class2,my_class3,my_class4)
