An example Code for Singleton Class

singleton_class_example.py

class Singleton:


    objects_created = 0
    
    def __new__(cls,*args,**kwargs):

        if cls.objects_created >= 1:
            raise ValueError("This is a Singleton Class, can't create more objects!")
            
        cls.objects_created +=1
        return super().__new__(cls)
    
    def __del__(self):
        
        Singleton.objects_created -=1
        
    def __init__(self):
        
        print("Object Created, present count of object(s):" + str(Singleton.objects_created))


object1 = Singleton() #Object Created, number of created objects=1
object2 = Singleton()
'''
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-59-d021da9b783b> in <module>()
----> 1 object2 = Singleton()

<ipython-input-57-1799f9006989> in __new__(cls, *args, **kwargs)
      3     def __new__(cls,*args,**kwargs):
      4         if cls.objects_created >= 1:
----> 5             raise ValueError("This is a Singleton Class, can't create more objects!")
      6         cls.objects_created +=1
      7         print ("Object Created, number of created objects=" + str(cls.objects_created))

ValueError: This is a Singleton Class, can't create more objects!
'''
del object1
Singleton.objects_created #0
object2 = Singleton() #Object Created, number of created objects=1