static RedundantCollectionOperationHandler handler(PsiMethodCallExpression call) {
      if(!PsiUtil.isAvailable(JavaFeature.OBJECTS_CLASS, call)) return null;
      PsiMethodCallExpression qualifierCall = MethodCallUtils.getQualifierMethodCall(call);
      if (!SINGLETON.test(qualifierCall)) return null;
      return new SingletonContainsHandler();
    }
static RedundantCollectionOperationHandler handler(PsiMethodCallExpression call)