Sorting by meta date

<?php

$job_seeker_experience_fieldset = get_user_meta($job_seeker_id, 'ngoh_usr_experience_fieldset', true);

// Sort the array according to most recently STARTED position
function compare_date($a, $b){
    // sort by year
    $retval = strnatcmp($a['started_year'], $b['started_year']);
    // if years are identical, sort by month
    if(!$retval) $retval = strnatcmp($a['started_month'], $b['started_month']);
    return $retval;
}

// do the sorting using the processing function
usort($job_seeker_experience_fieldset, __NAMESPACE__ . '\compare_date');
// reverse the array to make it descending
$reversed_experience = array_reverse($job_seeker_experience_fieldset);