Exception ignored in: <bound method BaseSession.__del__ of <tensorflow.python.client.session.Session object at 0x7fd3edd13e10>>
Traceback (most recent call last):
File "venv/lib/python3.5/site-packages/tensorflow/python/client/session.py", line 712, in __del__
TypeError: 'NoneType' object is not callable
解決方法：
from keras import backend as K K.clear_session()
參考：
https://stackoverflow.com/questions/40560795/tensorflow-attributeerror-nonetype-object-has-no-attribute-tf-deletestatus