How to run the demo.py?

[NunoDuarte]

Hi, thanks for you code. I'm trying to run demo.py and this comes up:

Traceback (most recent call last):
  File "demos.py", line 8, in <module>
    from ravens import Dataset
ImportError: cannot import name 'Dataset' from 'ravens' (unknown location)

The folder ravens seems to be missing a few things:

import argparse
import os

import numpy as np

from ravens import Dataset
from ravens import Environment
from ravens import tasks
import pdb
import pybullet as p

Any suggestions?