Hello,

mypy

is complaining when attempting to unpack a tuple returned from a task. In the example below, when attempting to unpack

a

&

b

from the call to

get_numbers

,

mypy

raises the error

"None" object is not iterable

. However, the type definition for the

get_numbers

function shows that

None

should never be returned from the task. Any idea what's wrong here? (Prefect v2.10.10, mypy v1.3.0)

from prefect import flow, task


@task
def get_numbers(a: int, b: int) -> tuple[int, int]:
    return a, b


@flow
def get_numbers_flow() -> None:
    a, b = get_numbers(1, 2)   # <- "None" object is not iterable.

I think the issue is to do with the

@task

decorator.

mypy

mightt be type checking against what is now a wrapped function - wrapped via the

task

decorator. I am not too sure what can be done about this. If you use

get_numbers.submitt(1,2)

do you get a similar warning?

Hi @Tim Galvin -- This has changed the warning to

"None" has no attribute "submit"

from

mypy

.