@flow

from prefect import flow, task

@task(name="Print Hello")
def print_hello(name):
    msg = f"Hello {name}!"
    print(msg)
    return msg

@flow(name="My Subflow")
def my_subflow(msg):
    print(f"Subflow says: {msg}")

@flow(name="Hello Flow")
def hello_world(name="world"):
    message = print_hello(name)
    my_subflow(message)

hello_world("Marvin")