printTree method
Implementation
void printTree([String prefix = ""]) {
final children = dependencies!;
final lastIndex = children.length - 1;
print('$prefix+- ${report()}');
for (var i = 0; i < children.length; i++) {
final child = children[i];
final childPrefix = (i == lastIndex) ? '$prefix ' : '$prefix| ';
child.printTree(childPrefix);
}
}