singleton.py

class DatabaseConnection:
    
    __dbInstance = None
    
    @classmethod
    def getInstance(cls):
        if cls.__dbInstance is None:
            cls.__dbInstance = cls()
            cls.__dbInstance.connect()
        return cls.__dbInstance
        
    def connect(self):
        print("Connected to database")
        
if __name__ == "__main__":
    
    print(DatabaseConnection.getInstance() == DatabaseConnection.getInstance())