Babel get error: unknown option `--modules'

Hello, this is my setting.py

``` py
# myapp/setting.py
STATIC_PRECOMPILER_COMPILERS = (
 # ...
  ('static_precompiler.compilers.Babel',{'modules':"transform-es2015-classes,transform-react-jsx"}),
  # ...
)
```

I don't know why I get this error 

I use this with the wrong way?
