Dart 2 runtime failures in test

[keertip]

type '(dynamic) => dynamic' is not a subtype of type '(String) => bool' in type cast
dart:core Object._as
package:boolean_selector/src/evaluator.dart 21:25 new Evaluator
package:boolean_selector/src/impl.dart 33:52 BooleanSelectorImpl.evaluate
../../dart/boolean_selector/test/evaluate_test.dart 58:19 _eval

[keertip]

@nex3 could you fix? Thanks!