Can't use XGBoost Classifier with face_recognition

• face_recognition version: Latest Version
• Python version: 3.6
• Operating System: Windows 10 x64

Hello!
I saw the using sklearn.Kneighbour classifier with face_recognition example. It works great, but I want to use Classifier from xgboost library to get my face recognition system more accurate.

I tried to modificate some example code to use XGBClassifier, but it generates following WARNINGS and does not recognition anything.

WARNINGS like this:
Warning (from warnings module):
File "C:\Program Files\Python36\lib\site-packages\sklearn\preprocessing\label.py", line 151
if diff:
DeprecationWarning: The truth value of an empty array is ambiguous. Returning False, but in future this will result in an error. Use array.size > 0 to check that an array is not empty.

But, original code works well.

I'm attaching my code. Most likely, the problem inside the "predict" function.
Please, help me. Sorry for my terrible English, I am Ukrainian.

Link to code: https://pastebin.com/Ceiqr3wN

Compare the attached Pastebin code with the working sklearn.Kneighbour face_recognition example, focusing first on the predict function and the sklearn preprocessing warning. Determine why the XGBClassifier path produces no recognition, and consider the issue done when it recognizes faces without the reported warning.