rknn-toolkit1.6 accuracy_analysis报Exception

rknn-toolkit1.6：调用hybrid_quantization_step2后，再调用accuracy_analysis，报下面的exception.
rknn.accuracy_analysis()
E Catch exception when snapshot: AttributeError("'NoneType' object has no attribute 'load_quantize'",)
E Traceback (most recent call last):
E   File "rknn/api/rknn_base.py", line 766, in rknn.api.rknn_base.RKNNBase.accuracy_analysis
E   File "rknn/api/rknn_base.py", line 1838, in rknn.api.rknn_base.RKNNBase._accuracy_analysis
E AttributeError: 'NoneType' object has no attribute 'load_quantize'

但是调用bulid_model后，再调用accuracy_analysis，就正常。请问这个是什么问题？看USER_MANUAL, accuracy_analysis可以在hybrid_quantization_step2之后调用啊。

应该在step1之后调用，之前文档有点问题