code: public static int optInt(@Nullable Bundle bundle, @Nullable String key, int fallback) {
          if (bundle == null) {
              return fallback;
          }
          return bundle.getInt(key, fallback);
      }
docs: Returns a optional int value. In other words, returns the value mapped by key if it exists and is a int.
  The bundle argument is allowed to be {@code null}. If the bundle is null, this method returns a fallback value.
  @param bundle a bundle. If the bundle is null, this method will return a fallback value.
  @param key a key for the value.
  @param fallback fallback value.
  @return a int value if exists, fallback value otherwise.
  @see android.os.Bundle#getInt(String, int)