Search term handler method

searchterm_handler.php

<?php
public function searchterm_handler($searchterm)
{
    if($searchterm)
    {
        $this->session->set_userdata('searchterm', $searchterm);
        return $searchterm;
    }
    elseif($this->session->userdata('searchterm'))
    {
        $searchterm = $this->session->userdata('searchterm');
        return $searchterm;
    }
    else
    {
        $searchterm ="";
        return $searchterm;
    }
}