isIn method Null safety

bool? isIn(
  1. Iterable<String?> strings
)

Checks if the String exists in a given Iterable<String>

Example

String foo = '6d64-4396-8547-1ec1b86e081e'
var iterable = ['fff','gasd'];
bool isIn = foo.isIn(iterable) // returns false

Implementation

bool? isIn(Iterable<String?> strings) {
  if (this == null) {
    return null;
  }
  if (this!.isEmpty) {
    return null;
  }
  return strings.contains(this);
}