Possible changes in the load_data_from_dir function

Hi Chi-Ruei Li,

thanks for the amazing implementation of the paper!

In the function _load_data_from_dir_ in _utils.py_ you use:
`b_tm1 = list(set(l[1:-1]))`
using a _set_ you change the order of the sequence, additionally you remove repetition of the items.

I would instead use
`b_tm1 = np.asarray(l)[1:-1].tolist()`

What are your thoughts on this?

Thanks,

Giuseppina