Get registry storage

		:return: WTaskDependencyRegistryStorage

def registry_storage(cls):
		""" Get registry storage

		:return: WTaskDependencyRegistryStorage
		"""
		if cls.__registry_storage__ is None:
			raise ValueError('__registry_storage__ must be defined')
		if isinstance(cls.__registry_storage__, WTaskDependencyRegistryStorage) is False:
			raise TypeError(
				"Property '__registry_storage__' is invalid (must derived from WTaskRegistryBase)"
			)

		return cls.__registry_storage__