 Unable to use TGAT or DySAT

When running models TGAT or DySAT, an error occurs:
```
  File "/home/jovyan/tgl/modules.py", line 57, in forward
    rst = self.layers['l' + str(l) + 'h' + str(h)](mfgs[l][h])
TypeError: 'NoneType' object is not subscriptable
```