[Question] How to define a parameter based on a defined one

In `config.gin`, I cannot do something like
```python
GAT.embed_dim = 30 # this is for init of GAT

Attention.node_ft_dim = GAT.__init__.embed_dim
# Attention.node_ft_dim = GAT.embed_dim # this won't work too
```
It won't work even when I
```
@gin.register
@gin.configurable
class GAT(nn.Module):
```

Is this feature implemented?