inverseOperator property Null safety

Implementation

PredicateOperator get inverseOperator {
  switch (operator) {
    case PredicateOperator.lessThan:
      return PredicateOperator.greaterThanEqualTo;
    case PredicateOperator.greaterThan:
      return PredicateOperator.lessThanEqualTo;
    case PredicateOperator.notEqual:
      return PredicateOperator.equalTo;
    case PredicateOperator.lessThanEqualTo:
      return PredicateOperator.greaterThan;
    case PredicateOperator.greaterThanEqualTo:
      return PredicateOperator.lessThan;
    case PredicateOperator.equalTo:
      return PredicateOperator.notEqual;
  }
}