IndexError: list index out of range

[ivyleavedtoadflax]

When running python main_threeTasks.py (from ./crf_baseline) I get the following error:

/home/matthew/Documents/wellcome/LinkedBooksDeepReferenceParsing/crf_baseline/build/virtualenv/lib/python3.7/site-packages/sklearn/externals/joblib/__init__.py:15: DeprecationWarning: sklearn.externals.joblib is deprecated in 0.21 and will be removed in 0.23. Please import this functionality directly from joblib, which can be installed with: pip install joblib. If this warning is raised when loading pickled models, you may need to re-serialize those models with scikit-learn 0.21+.
  warnings.warn(msg, category=DeprecationWarning)
Traceback (most recent call last):
  File "main_threeTasks.py", line 22, in <module>
    X_train_w, train_t1, train_t2, train_t3 = load_data("../dataset/clean_train.txt")
  File "/home/matthew/Documents/wellcome/LinkedBooksDeepReferenceParsing/crf_baseline/code/utils.py", line 50, in load_data
    tags4.append(w[4])
IndexError: list index out of range