ValueError("Tensor %s is not an element of this graph." % obj) on flask

[kkhzz1004]

when i run thin on flask.
i got this , anyone help me please?

Traceback (most recent call last):
File "C:\Users\kkhzz\Anaconda3\lib\site-packages\flask\app.py", line 1997, in call
return self.wsgi_app(environ, start_response)
File "C:\Users\kkhzz\Anaconda3\lib\site-packages\flask\app.py", line 1985, in wsgi_app
response = self.handle_exception(e)
File "C:\Users\kkhzz\Anaconda3\lib\site-packages\flask\app.py", line 1540, in handle_exception
reraise(exc_type, exc_value, tb)
File "C:\Users\kkhzz\Anaconda3\lib\site-packages\flask_compat.py", line 33, in reraise
raise value
File "C:\Users\kkhzz\Anaconda3\lib\site-packages\flask\app.py", line 1982, in wsgi_app
response = self.full_dispatch_request()
File "C:\Users\kkhzz\Anaconda3\lib\site-packages\flask\app.py", line 1614, in full_dispatch_request
rv = self.handle_user_exception(e)
File "C:\Users\kkhzz\Anaconda3\lib\site-packages\flask\app.py", line 1517, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "C:\Users\kkhzz\Anaconda3\lib\site-packages\flask_compat.py", line 33, in reraise
raise value
File "C:\Users\kkhzz\Anaconda3\lib\site-packages\flask\app.py", line 1612, in full_dispatch_request
rv = self.dispatch_request()
File "C:\Users\kkhzz\Anaconda3\lib\site-packages\flask\app.py", line 1598, in dispatch_request
return self.view_functionsrule.endpoint
File "D:\hancom\ims_front\flaskstart.py", line 122, in upload_image
return detect_faces_in_image(file)
File "D:\hancom\ims_front\flaskstart.py", line 169, in detect_faces_in_image
emotion_prediction = emotion_classifier.predict(gray_face)
File "C:\Users\kkhzz\Anaconda3\lib\site-packages\keras\engine\training.py", line 1164, in predict
self._make_predict_function()
File "C:\Users\kkhzz\Anaconda3\lib\site-packages\keras\engine\training.py", line 554, in _make_predict_function
**kwargs)
File "C:\Users\kkhzz\Anaconda3\lib\site-packages\keras\backend\tensorflow_backend.py", line 2744, in function
return Function(inputs, outputs, updates=updates, **kwargs)
File "C:\Users\kkhzz\Anaconda3\lib\site-packages\keras\backend\tensorflow_backend.py", line 2546, in init
with tf.control_dependencies(self.outputs):
File "C:\Users\kkhzz\Anaconda3\lib\site-packages\tensorflow\python\framework\ops.py", line 5004, in control_dependencies
return get_default_graph().control_dependencies(control_inputs)
File "C:\Users\kkhzz\Anaconda3\lib\site-packages\tensorflow\python\framework\ops.py", line 4543, in control_dependencies
c = self.as_graph_element(c)
File "C:\Users\kkhzz\Anaconda3\lib\site-packages\tensorflow\python\framework\ops.py", line 3490, in as_graph_element
return self._as_graph_element_locked(obj, allow_tensor, allow_operation)
File "C:\Users\kkhzz\Anaconda3\lib\site-packages\tensorflow\python\framework\ops.py", line 3569, in _as_graph_element_locked
raise ValueError("Tensor %s is not an element of this graph." % obj)