function like python range in dart
List<num> range({required num endNum , required num startNum}) {
List<num> progression = [];
if (startNum < endNum) {
while (startNum < endNum - 1) {
startNum++;
progression.add(startNum);
}
} else if (startNum > endNum) {
while (startNum > endNum + 1) {
startNum--;
progression.add(startNum);
}
}
return progression;
}