```from .nnet import *``` in ```theano/tensor/nnet/__init__.py``` is
causing problems because ```nnet``` imports ```theano.tensor.opt``` as
```opt``` which takes namespace place of ```theano.tensor.nnet.opt```.

To fix this problem, I replace ```from .nnet import *``` by ```from
.nnet import (every class/functions/attributes)```

Added the following code at the end of the file
```theano/tensor/nnet/nnet.py```

```python
print locals().keys()
```

And then copied the output

```bash
$ python theano/tensor/nnet/nnet.py
['keys', 'of', 'locals', ...]
```

Removed last line of code in ```theano/tensor/nnet/nnet.py``` and added
following code under the imports

```python
keys = ['keys', 'of', 'locals', ...]  # pasted the copied output from
previous step
local_keys = locals().keys()
keep = filter(lambda a: a not in local_keys and a[0] != '_', keys)
print sorted(keep)
```
And again

```bash
$ python theano/tensor/nnet/nnet.py
['keys', 'of', 'locals', 'minus', 'imports', 'and', 'private'...]
```

Those are the class/function names to be added to
```theano/tensor/nnet/__init__.py```.

```python
from .nnet import (
    keys, of, locals, minus, imports,
    and, private, ...)
```