sub get_hash_key {
  my ($h, @keys) = @_;

  my $v = $h;
  $v = $v->{$_} foreach @keys;
  return $v;
}
##</code><code>##

sub get_hash_key_ref {
  my ($h, @keys) = @_;

  my $r = \$h;
  $r = \$$r->{$_} foreach @keys;
  return $r;
}