Script check method

scriptCheck.php

public function scriptCheck() {

	global $wpdb;
	
	$wnumber = $this->getWNumber();
	
	$booking_status = $wpdb->get_results("SELECT completed FROM " . $wpdb->prefix . "ch_bookings WHERE booking = " . $wnumber, ARRAY_A);
	
	if (is_array($booking_status)) {
		if ($booking_status[0]["completed"] == 1) {
			return true;
		}
	}
	else {
		$wpdb->insert($wpdb->prefix . 'ch_bookings', 
			array( 
				'booking' => $wnumber, 
				'completed' => 1,
			)
		);
		return false;
	}
}

Need to change line 9:
if (is_array($booking_status) && ($booking_status[0]['completed'] ?? '' == 1)) {
return true;
}