def blink(self, interval: float = <NUM_LIT>, n: int = <NUM_LIT:3>):
for i in range(n):<EOL><INDENT>self.all_on()<EOL>time.sleep(interval / <NUM_LIT:2>)<EOL>self.all_off()<EOL>time.sleep(interval / <NUM_LIT:2>)<EOL><DEDENT>
Blink all the lights on and off at once.
NOTE! Does not remember prior state of lights and will finish
with all lights off.
:param interval: The length in seconds of an ON/OFF cycle
:param n: How many times to cycle ON and OFF
:return: