Missing file optimizer.py in pip install

To reproduce:
Install gans2
```
pip install gans2
```

attempt to import optimizer:
```python
from gans.trainers import optimizers
```
Expected result:
```
```

Actual result:
```
ImportError: cannot import name 'optimizers' from 'gans.trainers' (c:\users\**PATH**\lib\site-packages\gans\trainers\__init__.py)
```
```