Source code for

[docs]class Singleton(type): """ The `singleton pattern <>`_ is a software design pattern that restricts the instantiation of a class to one object. *Note*: The implementation idea is borrowed from "`Creating a singleton in Python <>`_" question on StackOverflow. """ _instances = {} def __call__(cls, *args, **kwargs): if cls not in cls._instances: cls._instances[cls] = super(Singleton, cls).__call__(*args, **kwargs) return cls._instances[cls]
[docs] @classmethod def delete(cls, singleton_cls): ''' The method for an intentional removal of the singleton object. It shouldn't be used unless you really know what you are doing. One use case is a unit test, which removes an Application object after each iteration. ''' del cls._instances[singleton_cls]