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In order to cancel the rest of the pipeline on error I'm returning `Failed(message=...)` from one of my tasks. I can type-annotate this function to say that it returns either an object _or_ a state, but this seems like more negative engineering in my calling code when in 99% of all cases it returns an object. When calling `.fn()` in my test `return_state` is not available as a parameter, which would inform my type-checker that the result is actually a state.

Is there a better way to fail my pipeline, or a better way to perform this assert in my test?

Seems like maybe a type-guard is the safest and simplest option:
```from prefect.server.schemas.states import State

maybe_result = tasks.some_task(p1="test")
assert isinstance(maybe_result, State)
assert maybe_result.is_failed()```
This allows the type-checker to verify that the `is_failed` method exists on  `maybe_result`.