Training in demo-webcam

[CaptainCuong]

After executing the line

f.train()

The following error is returned

ValueError                                Traceback (most recent call last)
<ipython-input-10-770cb541f283> in <module>()
----> 1 f.train()

<ipython-input-7-720c27c39f20> in train(self)
     73             embs.append(embs_)
     74 
---> 75         embs = np.concatenate(embs)
     76         le = LabelEncoder().fit(labels)
     77         y = le.transform(labels)

<__array_function__ internals> in concatenate(*args, **kwargs)

ValueError: need at least one array to concatenate

What is the problem? And how to solve it?

[CaptainCuong]

Anyone can use webcam to capture the image?