TypeError: '<' not supported between instances of 'tuple' and 'list'

[MuhammadUsmanSCUT]

I am running the code for dataset 2 from wyrm/examples/BCI Competition 3, Data Set 2 (P300 Speller).ipynb. during running of last step I am facing the error "TypeError: '<' not supported between instances of 'tuple' and 'list'".

TypeError Traceback (most recent call last)
in
14
15 # load the training set
---> 16 dat = load_bcicomp3_ds2(training_set)
17 fv_train, epo[subject] = preprocessing(dat, MARKER_DEF_TRAIN, jumping_means_ivals)
18 # train the lda

/opt/conda/lib/python3.7/site-packages/wyrm/io.py in load_bcicomp3_ds2(filename)
486 markers.extend(nontargets)
487 markers.extend(stimulus_code)
--> 488 markers.sort()
489 dat.markers = markers[:]
490 return dat

TypeError: '<' not supported between instances of 'tuple' and 'list'