This plugin is based on authorised values from INVENTORY. It is used for stocknumber computation.
If no prefix is submitted, or the prefix does contain only numbers, it returns the inserted code (= keep the field unchanged).
If a prefix is submitted, we look for the highest stocknumber with this prefix and return it incremented.
In this case, a stocknumber has this form (e.g. "PREFIX 0009678570"): PREFIX containing letters, a space separator and 10 digits with leading 0s if needed.