use strict; use warnings FATAL => 'all';
my $hr = hash( baz => undef, foo => 'bar' );
my $kv = $hr->kv;
my @sorted = $kv->sort_by(sub { $_->[0] })->all;
is_deeply
\@sorted,
[
[ baz => undef ],
[ foo => 'bar' ],
],
'kv ok';
done_testing;