How to use the simgrid.Actor.by_pid function in simgrid

def killer():
    this_actor.info("Hello!")  # - First start a victim process
    victim_a = Actor.create("victim A", Host.by_name("Fafard"), victim_a_fun)
    victim_b = Actor.create("victim B", Host.by_name("Jupiter"), victim_b_fun)
    this_actor.sleep_for(10)  # - Wait for 10 seconds

    # - Resume it from its suspended state
    this_actor.info("Resume the victim A")
    victim_a.resume()
    this_actor.sleep_for(2)

    this_actor.info("Kill the victim A")   # - and then kill it
    Actor.by_pid(victim_a.pid).kill()       # You can retrieve an actor from its PID (and then kill it)

    this_actor.sleep_for(1)

    # that's a no-op, there is no zombies in SimGrid
    this_actor.info("Kill victim B, even if it's already dead")
    victim_b.kill()

    this_actor.sleep_for(1)

    this_actor.info("Start a new actor, and kill it right away")
    victim_c = Actor.create("victim C", Host.by_name("Jupiter"), victim_a_fun)
    victim_c.kill()

    this_actor.sleep_for(1)

    this_actor.info("Killing everybody but myself")