@Override
  public Object visitWildcardType(@NotNull PsiWildcardType wildcardType) {
    builder.append('?');
    PsiType bound = wildcardType.getBound();
    if (bound == null) return this;
    if (wildcardType.isExtends()) {
      builder.append(" extends ");
    }
    else {
      builder.append(" super ");
    }
    bound.accept(this);
    return this;
  }
@Override
  public Object visitWildcardType(@NotNull PsiWildcardType wildcardType)