public @NotNull <T extends JsonValue> T createValue(@NotNull String content) {
    final PsiFile file = createDummyFile("{\"foo\": " + content + "}");
    //noinspection unchecked,ConstantConditions
    return (T)((JsonObject)file.getFirstChild()).getPropertyList().get(0).getValue();
  }
public @NotNull <T extends JsonValue> T createValue(@NotNull String content)