words ending with 'ss' singular_noun might not work

Curious as I got the singular_noun of "grass" as "gras". I am on python 3.11

`import inflect
p = inflect.engine()
p.singular_noun("grass") # 'gras'`

edit: 'glass,underpass' as well. may be if a word is ending with 'ss' singular_noun might not work.

Start by reproducing the singular_noun examples for “grass”, “glass”, and “underpass” with Python 3.11. Trace the singular_noun entry point and the pluralization rules it uses, then confirm that these words return the expected singular form without changing other cases.

Written by the indexing model from the issue text.