How to use the simgrid.Comm function in simgrid

# Create a communication representing the ongoing communication, and store it in pending_comms
            comm = mbox.put_async(content, self.msg_size)
            pending_comms.append(comm)

        # Start sending messages to let the workers know that they should stop
        for i in range(0, self.receivers_count):
            mbox = mboxes[i]
            this_actor.info("Send 'finalize' to '{:s}'".format(str(mbox)))
            comm = mbox.put_async("finalize", 0)
            pending_comms.append(comm)

        this_actor.info("Done dispatching all messages")

        # Now that all message exchanges were initiated, wait for their completion in one single call
        Comm.wait_all(pending_comms)

        this_actor.info("Goodbye now!")

# Start sending messages to let the workers know that they should stop
        for i in range(0, self.receivers_count):
            mbox = mboxes[i]
            this_actor.info("Send 'finalize' to '{:s}'".format(str(mbox)))
            comm = mbox.put_async("finalize", 0)
            pending_comms.append(comm)

        this_actor.info("Done dispatching all messages")

        # Now that all message exchanges were initiated, wait for their completion, in order of completion.
        #
        # This loop waits for first terminating message with wait_any() and remove it with del, until all comms are
        # terminated.
        # Even in this simple example, the pending comms do not terminate in the exact same order of creation.
        while pending_comms:
            changed_pos = Comm.wait_any(pending_comms)
            del pending_comms[changed_pos]
            if (changed_pos != 0):
                this_actor.info(
                    "Remove the {:d}th pending comm: it terminated earlier than another comm that was initiated first.".format(changed_pos))

        this_actor.info("Goodbye now!")