private function encode($data)
{
if (is_resource($data)) {
throw new InvalidArgumentException('Cannot encode resources');
}
// just print to console as key-value pair
$output = [];
array_walk_recursive($data, function ($value, $key) use(&$output) {
$output[] = $key . ': ' . $value;
});
return join("\n", $output) . "\n";
}