def strip_reason(reason):
return re.sub('<STR_LIT>', '<STR_LIT>', reason)<EOL>
only the following characters are allowed:
'0-9', 'a-z', 'A-Z', ' ', '+', ',', '-', '.'.
Umlauts are replaced, e.g. ä -> ae.

@see: https://www.sofort.com/integrationCenter-eng-DE/content/view/full/2513#h5-1