Function sort 

pub fn sort(key_arg: &str) -> FnOptionArg

Sort based on the key given. Prefix - to sort in descending order of the value. You may use the –sort= option multiple times, in which case the last key becomes the primary key. Also supports “version:refname” or “v:refname” (tag names are treated as versions). The “version:refname” sort order can also be affected by the “versionsort.suffix” configuration variable. The keys supported are the same as those in git for-each-ref. Sort order defaults to the value configured for the tag.sort variable if it exists, or lexicographic order otherwise. See git-config(1). –sort=