def build_and_start ( query , directory ) : Async ( target = grep , args = [ query , directory ] ) . start ( )
asterisk notation in python 3 passing async functions
This function will create and then start a new Async task with the default callbacks argument defined in the decorator .
def build_and_start(query, directory):
    """This function will create and then start a new Async task with the
    default callbacks argument defined in the decorator."""

    Async(target=grep, args=[query, directory]).start()