cases (except for `duplicates' and `sorted'), the first non-nil value among
all the backends is returned.
-The group can also contain keywords. Currently, `:with' and `:sorted'
+The group can also contain keywords. Currently, `:with' and `:sorted'
keywords are defined. If the group contains keyword `:with', the backends
listed after this keyword are ignored for the purpose of the `prefix'
command. If the group contains keyword `:sorted', the final list of