Display animation to show activity.

def busy_display():
    """Display animation to show activity."""
    sys.stdout.write("\033[?25l")  # cursor off
    sys.stdout.flush()
    for x in range(1800):
        symb = ['\\', '|', '/', '-']
        sys.stdout.write("\033[D{}".format(symb[x % 4]))
        sys.stdout.flush()
        gevent.sleep(0.1)