Use of LBPHFaceRecognizer (python)

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I am testing the python version of LBPHFaceRecognizer and results seems not bad, but I noted something strange. Making the prediction, let's say:

label= face_recognizer.predict(gray)
print('prediction', label)

I see that label is a tuple with 2 values, the first is the prediction, the second I guess is the probability. Now when probability is low the prediction is fine, while when it is high, I have false positive.

Maybe this value is not the probability, so the question is, what is its real meaning ? Thanks