def METHOD_NAME(self, result):
    if not hasattr(result, 'errorClasses'):
        self.patchResult(result)
    for cls, (storage_attr, label, isfail) in self.errorClasses:
        if cls not in result.errorClasses:
            storage = getattr(result, storage_attr, [])
            setattr(result, storage_attr, storage)
            result.errorClasses[cls] = (storage, label, isfail)