Import error Trainer in Train Pipeline

[sigeisler]

Hi,

the following line throws an error:

https://github.com/THUDM/grb/blob/master/pipeline/train_pipeline.py#L8

Traceback (most recent call last):
  File "/nfs/homedirs/geisler/code/grb/pipeline/train_pipeline.py", line 8, in <module>
    from grb.utils import Trainer, Logger
ImportError: cannot import name 'Trainer' from 'grb.utils' (/nfs/homedirs/geisler/code/grb/grb/utils/__init__.py)

[LeeBC2298]

similar problem: AttributeError: module 'grb' has no attribute 'utils'