parsePair function
Parses a key-value string and returns the Pair representation. A key-value string looks like:
"someKey=someValue"
Implementation
Pair<String, String> parsePair(String pair) {
final pairElements = pair.split('=');
if (pairElements.length != 2) {
throw TellUser((tell) => tell(red("Only one '=' per key value pair ")));
}
final key = pairElements[0].trim();
final value = pairElements[1].trim();
return Pair(key: key, value: value);
}