The encoding() method returns one of the following values:

    * 0: Unknown format. This shouldn't happen. In the default case the format should be 1.
    * 1: 8bit ASCII or single byte UTF-16. This indicates that the characters are encoded in a single byte. In Excel 95 and earlier This usually meant ASCII or an international variant. In Excel 97 it refers to a compressed UTF-16 character string where all of the high order bytes are 0 and are omitted to save space.
    * 2: UTF-16BE.
    * 3: Native encoding. In Excel 95 and earlier this encoding was used to represent multi-byte character encodings such as SJIS.