ios - How do I construct a HealthKit HKUnit for mmol/L (millimoles per liter) for Blood Glucose values? -

blood glucose values added in health in ios 8.2: https://support.apple.com/en-us/ht203113

how construct healthkit hkunit mmol/l (millimoles per liter) blood glucose values?

the following both throw exceptions: terminating app due uncaught exception 'nsinvalidargumentexception', reason: 'unable parse factorization string...

hkunit *mmolperl = [hkunit unitfromstring:@"mmol<molar mass>/l"]; hkunit *mmolperl = [hkunit unitfromstring:@"mmol/l"]; 

can confirm examples provided don't work (every permutation), alternative mg/dl unit does.

to sum up, both proposed approaches work, similar (with approach proposed @cbartel constant rounded, not other) results regarding structure of resulting hkunit:

printing description of mmolperl->_baseunits->_factors: nsmaptable { [6] mmol<180.15588> -> 1 [7] l -> -1 } 

i'd use shorter form using provided constant:

hkunit *mmolperl = [hkunit unitfromstring:[nsstring stringwithformat:@"mmol<%f>/l",hkunitmolarmassbloodglucose]];