my $tmpl = {
    _data   => [ ],
    _file   => 'Unknown',
};

for my $key ( keys %$tmpl ) {
    no strict 'refs';
    *{__PACKAGE__."::$key"} = sub {
        my $self = shift;
        $self->{$key} = $_[0] if @_;
        return $self->{$key};
    }
}