Delay some seconds
        Args:
            secs: float seconds

        Returns:
            self

def delay(self, secs):
        """Delay some seconds
        Args:
            secs: float seconds

        Returns:
            self
        """
        secs = int(secs)
        for i in reversed(range(secs)):
            sys.stdout.write('\r')
            sys.stdout.write("sleep %ds, left %2ds" % (secs, i+1))
            sys.stdout.flush()
            time.sleep(1)
        sys.stdout.write("\n")
        return self