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