sqlite_backend => [
                {   'DBIx::Simple' => '0.0',
                    'DBD::SQLite'  => '0.0',
                },
                sub {
                    my $cb   = shift;
                    my $conf = $cb->configure_object;
                    return $conf->get_conf('source_engine')
                        eq 'CPANPLUS::Internals::Source::SQLite'
                },