docs: @Nullable
    public String getListItemStartingWith (@Nullable final String sPrefix)
    {
      for (final Object aObj : m_aList)
        if (aObj instanceof List <?>)
          for (final Object aListItem : (List <?>) aObj)
            if (((String) aListItem).startsWith (sPrefix))
              return (String) aListItem;
      return null;
    }