main function
void
main()
Implementation
void main() {
// Example: Lookup symbol for a valid unit code
String? symbol = parseUnitCode('23');
print('Symbol for unit code 23: $symbol'); // Output: g/cm³
// Example: Validate a unit code
bool isValid = isUnitCodeValid('23');
print('Is unit code 23 valid? $isValid'); // Output: true
// Example: Lookup symbol for an invalid unit code
String? invalidSymbol = tryParseUnitCode('FOO');
print('Symbol for unit code FOO: $invalidSymbol'); // Output: null
}