@Override
    public ApiException getError() {
      if (successful()) {
        return null;
      }
      return ApiException.from(status, errorMessage);
    }
Specifies the field masks of the details to be returned by PlaceDetails.

@param fields The Field Masks of the fields to return.
@return Returns this {@code PlaceDetailsRequest} for call chaining.
src/main/java/com/google/maps/PlaceDetailsRequest.java