sub is_hash {
  my($hash, @keys) = @_;
  return unless defined $hash && ref($hash) eq 'HASH';
  return $hash unless @keys;

  my $yes;
  for (@keys) {
    $yes = undef,
      last unless ref $hash eq 'HASH' && %{ $hash };

    $yes = undef,
      last unless exists $hash->{$_} &&
                 defined $hash->{$_};

     $yes = 1;
     $hash = $hash->{$_};
  }

  return $yes ? $hash : $yes;
}