AttributeError: 'module' object has no attribute 'AbstractModule'

```python
Matplotlib required for plot()
Traceback (most recent call last):
File "evaluate.py", line 26, in
import meta
File "/Users/tomato/Sites/learning-to-learn/meta.py", line 32, in
import networks
File "/Users/tomato/Sites/learning-to-learn/networks.py", line 31, in
import preprocess
File "/Users/tomato/Sites/learning-to-learn/preprocess.py", line 26, in
class Clamp(snt.AbstractModule):
AttributeError: 'module' object has no attribute 'AbstractModule'
```
```sh
$ python -V
Python 2.7.13
$ pip -V
pip 9.0.1 from /usr/local/lib/python2.7/site-packages (python 2.7)
```