Hi i am going through the tutorials and https://docs.prefect.io/core/examples/mapping.html

from prefect import task

@task
def add(x, y):
    return x + y

add(1, 2)  # 3

this example throws me:

ValueError: Could not infer an active Flow context while creating edge

and suggests using add.run() instead. In the tutorial however, they use add(1,2) regularly. Are the tutorials outdated for the newest version of prefect? edit: I am also unable to use .map as it is used in the tutorial:

add.map([1, 10], [2, 3])

throws the same error? How am I supposed to experiment with tasks without flow context?

Hey Matej, each Prefect task has a

run()

method. If you run it in a flow context (

with Flow("flowname")...

), then this run() method is called automatically. But when you run it outside of a Flow context, you need to add the run method explicitly like so:

add.run(1, 2)

. Here is a slightly adjusted example from the docs:

from prefect import task, Flow

@task
def add(x, y):
    return x + y

@task(log_stdout=True)
def compute_sum(nums):
    total = sum(nums)
    print(f"total = {total}")
    return total

@task(log_stdout=True)
def print_map_output(nums):
    print(f"Mapping results: {nums}")

with Flow("mapping-example") as flow:
    addition_result = add.map([1, 10], [2, 3])  # [3, 13]
    print_map_output(addition_result)  # if you want to just see the map output
    compute_sum(addition_result)  # if you want to do something with the map output

if __name__ == '__main__':
    add.run(1, 2)  # standalone task run
    flow.run()  # run in a flow context