Issue with Keras

[JosjaG]

[ERROR][/hero/people_recognition/face_recognition/keras_face_properties][1576613239.376740]: Error processing request: Structure is a scalar but len(flat_sequence) == 0 > 1

Traceback (most recent call last):
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/rospy/impl/tcpros_service.py", line 625, in _handle_request
    response = convert_return_to_response(self.handler(request), self.response_class)
  File "/home/amigo/ros/kinetic/system/src/image_recognition_keras/scripts/face_properties_node", line 50, in _get_face_properties_srv
    estimations = self._estimator.estimate(bgr_images)
  File "/home/amigo/ros/kinetic/system/src/image_recognition_keras/src/image_recognition_keras/age_gender_estimator.py", line 51, in estimate
    results = self._model.predict(faces)
  File "/home/amigo/.local/lib/python2.7/site-packages/tensorflow_core/python/keras/engine/training.py", line 909, in predict
    use_multiprocessing=use_multiprocessing)
  File "/home/amigo/.local/lib/python2.7/site-packages/tensorflow_core/python/keras/engine/training_arrays.py", line 722, in predict
    callbacks=callbacks)
  File "/home/amigo/.local/lib/python2.7/site-packages/tensorflow_core/python/keras/engine/training_arrays.py", line 410, in model_iteration
    aggregator.finalize()
  File "/home/amigo/.local/lib/python2.7/site-packages/tensorflow_core/python/keras/engine/training_utils.py", line 349, in finalize
    self.results = nest.pack_sequence_as(self._structure, self.results)
  File "/home/amigo/.local/lib/python2.7/site-packages/tensorflow_core/python/util/nest.py", line 456, in pack_sequence_as
    % len(flat_sequence))
ValueError: Structure is a scalar but len(flat_sequence) == 0 > 1