If you are using PyTorch < 0.4.0, you have to wrap it into a Variable.
The most recent stable version is 0.4.0 where Variables and tensors were merged.
Have a look at the Migration Guide 27.
You’ll find the install instructions on the website 6.
The KeyError is strange. Have you registered the activation with get_activation('fc2')?
The name argument is used to store the activation in the dict, so I’m wondering, why the error happened.