xgboost-census-debugger-rules.ipynb failed CI

Link to the notebook:
https://github.com/aws/amazon-sagemaker-examples/blob/master/sagemaker-debugger/xgboost_census_explanations/xgboost-census-debugger-rules.ipynb

Error:

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Exception encountered at "In [6]":
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ModuleNotFoundError Traceback (most recent call last)
in
----> 1 import shap
2 X, y = shap.datasets.adult()
3 X_display, y_display = shap.datasets.adult(display=True)
4 feature_names = list(X.columns)

ModuleNotFoundError: No module named 'shap'