openfl.utilities.types.SingletonABCMeta

class openfl.utilities.types.SingletonABCMeta(name, bases, namespace, **kwargs)

Bases: ABCMeta

Metaclass for singleton instances.

This metaclass ensures that only one instance of any class using it can be created.

Class Attributes:

_instances (dict) – A dictionary mapping classes to their instances.

Methods

mro	Return a type's method resolution order.
register	Register a virtual subclass of an ABC.

__call__(*args, **kwargs)

Use the singleton instance if it has already been created.

Parameters:

• *args – Positional arguments to pass to the class constructor.

• **kwargs – Keyword arguments to pass to the class constructor.

Returns:

Any – The singleton instance of the class.

mro()

Return a type’s method resolution order.

register(subclass)

Register a virtual subclass of an ABC.

Returns the subclass, to allow usage as a class decorator.