anchor.diff:      });
   
       // print report
  -    final List<String> keys = usages.keys.toList();
  +    final keys = usages.keys.toList();
       keys.sort();
   
       print('${keys.length} separate Dart plugin APIs used:');
  
positive.code: 
      for (var import in keys) {
        print('$import:');
        List<String> places = usages[import];
        places.forEach((String place) => print('  $place'));
        print('');
      }
  
negative.code:     final String imports = result.stdout.trim();
  
      // path:import
      final usages = <String, List<String>>{};
  
      imports.split('\n').forEach((String line) {
        if (line.trim().isEmpty) {
  