Error with recent merge regarding sl proces

[DailyMeme]

This what happened after I typed in python src\chess_zero\run.py --cmd sl

Traceback (most recent call last):
File "src\chess_zero\run.py", line 20, in
manager.start()
File "src\chess_zero\manager.py", line 73, in start
return sl.start(config)
File "src\chess_zero\worker\sl.py", line 25, in start
return SupervisedLearningWorker(config).start()
File "src\chess_zero\worker\sl.py", line 55, in start
games = self.get_games_from_all_files()
File "src\chess_zero\worker\sl.py", line 79, in get_games_from_all_files
games.extend(get_games_from_file(filename))
File "src\chess_zero\worker\sl.py", line 118, in get_games_from_file
headers = chess.pgn.read_headers(pgn)
AttributeError: module 'chess.pgn' has no attribute 'read_headers'

This was not the case with the version 2 commits(?) earlier then it worked perfectly for me.
Does someone know what the problem is?