'Check if an object is safely callable.  Per default a function is
considered safe unless the `unsafe_callable` attribute exists and is
True.  Override this method to alter the behavior, but this won\'t
affect the `unsafe` decorator from this module.'

def is_safe_callable(self, obj):

    return (not (getattr(obj, 'unsafe_callable', False) or getattr(obj, 'alters_data', False)))
