I hope this is a relatively simple question: using prefect 2.0, how can I get a task to return two values? as a function it is something like

@task
def f(val):
   return val * 2, val * 4

then the call in my flow looks like

a, b = f.map([1, 2, 3])

but I get ValueError: not enough values to unpack (expected 2, got 1) I have confirmed that the code works as expected when not decorated with mapping over

@task

(that is, two inputs are returned)

The task returns the tuple you expect it to so just calling the task would work:

# in a flow
# should set a = 2 and b = 4
a, b = f(1)

But as you mentioned,

map

runs the task once for each of the input values, and you get back a list of futures. Each future will resolve to a tuple returned by one of the task runs. Running something like this in your flow might give you what you are looking for:

logger = get_run_logger()
futures = f.map([1, 2, 3])
for future in futures:
    a, b = future.result()
    <http://logger.info|logger.info>(f"a is {a}, b is {b}")

thanks, makes sense