No module named 'odtk' error when loading pickle file dataset

Running the following script
```
import core
dataset = core.data.load_sample("umons-all")
```
would result in a `ModuleNotFoundError: No module named 'odtk'` error, which is originated from `read_dataset(file_name)` method in core/data/io.py
```
from pickle import load
with open(file_name, 'rb') as file:
    dataset = load(file)
```
Any pointers? Thanks.