code: public static byte optByte(@Nullable Bundle bundle, @Nullable String key) {
          return optByte(bundle, key, (byte) 0);
      }
docs: Returns a optional byte value. In other words, returns the value mapped by key if it exists and is a byte.
  The bundle argument is allowed to be {@code null}. If the bundle is null, this method returns (byte) 0.
  @param bundle a bundle. If the bundle is null, this method will return a fallback value.
  @param key a key for the value.
  @return a boolean value if exists, (byte) 0 otherwise.
  @see android.os.Bundle#getByte(String)