multi_level_map.py

import time
from prefect import task, Flow
from prefect.engine.executors import DaskExecutor


@task
def times():
  return [1, 5, 10]


@task
def sleep(x):
  print(f'sleeping for {x}')
  time.sleep(x)
  print(f'done sleeping for {x}')
  return x


with Flow("mapping-test") as flow:
  sleep.map(sleep.map(times))


flow.run(executor=DaskExecutor())