value method
Implementation
int value(String ticker) {
var confirmedCollected = confirmed.map((key, value) =>
key == ticker ? MapEntry(ticker, value) : MapEntry(ticker, 0));
var unconfirmedCollected = unconfirmed.map((key, value) =>
key == ticker ? MapEntry(ticker, value) : MapEntry(ticker, 0));
return (confirmedCollected.values.fold(
0, (previousValue, value) => previousValue ?? 0 + value) as int) +
(unconfirmedCollected.values.fold(
0, (previousValue, value) => previousValue ?? 0 + value) as int);
}