mixItem method
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Implementation
List<T> mixItem(T item, {bool around = false}) {
List<T> result = [];
for (int i = 0; i < this.length; ++i) {
if (i == 0) {
if (around) {
result.add(item);
}
} else {
result.add(item);
}
result.add(this[i]);
}
if (around == true) {
result.add(item);
}
return result;
}