code: def tasks_by_tag(self, registry_tag):
  		
  		if registry_tag not in self.__registry.keys():
  			return None
  		tasks = self.__registry[registry_tag]
  		return tasks if self.__multiple_tasks_per_tag__ is True else tasks[0]
docs: Get tasks from registry by its tag
  
  		:param registry_tag: any hash-able object
  		:return: Return task (if :attr:`.WTaskRegistryStorage.__multiple_tasks_per_tag__` is not True) or \
  		list of tasks