"fade" method throws Exception when both params are None

[EAGrahamJr]

Adafruit_CircuitPython_IS31FL3731/adafruit_is31fl3731/__init__.py

Line 193 in 97eb72a

def fade(self, fade_in=None, fade_out=None, pause=0):

It seems there's a missing return that should occur when both parameters are None. If that does not occur, line 209 will (obviously) fail.

[tannewt]

Would you mind making a PR? I think you are right what the fix is. https://learn.adafruit.com/contribute-to-circuitpython-with-git-and-github