Subject of the issue

The function in utils/tool.py called is_user_member_of_an_allowed_group should really be renamed as the current name does not reflect what the function does anymore :

• The cardinality is wrong as it can be used with multiple groups
• The function is already used to check if member of a banned group

A possible new name could be is_user_member_of_groups_among(user, groups) but a better one could be found