public function getTree($arr, $parent_id, $name)
{
$tree = [];
foreach ($arr as $k => $v) {
if ($v['pid'] == $parent_id) {
$v['son'] = $this->getTree($arr, $v[$name], $name);
if ($v['son'] == null) {
unset($v['son']);
}
$tree[] = $v;
}
}
return $tree;
}