`sample:getFormat()` returns `4`

[BanksySan (David)]

sample:getFormat() is returning 4, but there isn't a format with a value of 4.

{
	[16bitMono] = 2,
	[16bitStereo] = 3,
	[8bitMono] = 0,
	[8bitStereo] = 1,
}
getSampleRate()	44100	getFormat	4	getLength()	0.1161224	0.1161224

I'm exporting from Audacity:

[scratchminer]

Values 4 and 5 are ADPCM mono and stereo -- not sure why those constants aren't defined in Lua though.