A decorator method that adds this class to a 'resources' list on the 
        decorated object.

def decorator(cls, func_or_class):
        """A decorator method that adds this class to a 'resources' list on the 
        decorated object."""
        resources = getattr(func_or_class, 'resources', [])
        resources.append(cls)
        func_or_class.resources = resources
        return func_or_class