public function get_scheme()
{
$scheme = [];
$titles = $this->get_scheme_titles();
foreach ($this->get_scheme_value() as $scheme_key => $scheme_value) {
$scheme[$scheme_key] = ['title' => isset($titles[$scheme_key]) ? $titles[$scheme_key] : '', 'value' => $scheme_value];
}
return $scheme;
}