Handling custom exception type from activities

I would like to understand if it is possible to handle custom exception type (from activities) inside the orchestrator function.

E.g.:

Activity
```python
raise MyException(custom_data={...})
```
Orchestrator:
```python
try:
res = yield context.call_activity("Activity", data)
except MyException as me:
print(me.custom_data)
```

The actual behaviour is that in the orchestrator function I only get the generic Exception type and I cannot differentiate the handle logic based on custom_data.