private void mapExtras() {
    Bundle extras = getIntent().getExtras();
    if (extras == null) {
      throwIllegalArgumentException();
    }
    tvShowId = extras.getString(EXTRA_TV_SHOW_ID);
    if (StringUtils.isNullOrEmpty(tvShowId)) {
      throwIllegalArgumentException();
    }
  }
As TvShowId is mandatory if there is no an extra inside the bundle that launches this activity
we are going to throw a new IllegalArgumentException.
app/src/main/java/com/github/pedrovgs/effectiveandroidui/ui/activity/TvShowActivity.java