convertValue method
Returns value, converted to the units represented by newNumerators and
newDenominators.
Throws a SassScriptException if this number's units aren't compatible
with newNumerators and newDenominators or if this number is unitless.
If this came from a function argument, name is the argument name
(without the $). It's used for error reporting.
Implementation
double convertValue(List<String> newNumerators, List<String> newDenominators,
[String? name]) =>
_coerceOrConvertValue(newNumerators, newDenominators,
coerceUnitless: false, name: name);