optList method
returns the value corresponding with key
as nullable List<String>
if null returns defaultValue
Implementation
List<String>? optList(String key, [List<String>? defaultValue]) {
var val = _params[key];
if (val == null) {
return defaultValue;
}
if (val is List) {
return val.map((e) => e.toString()).toList();
} else {
return [val.toString()];
}
}