public function add_fee($args, $global = true)
{
$default_args = array('label' => '', 'amount' => 0, 'type' => 'fee', 'id' => '', 'price_id' => 0);
$fee = wp_parse_args($args, $default_args);
$this->fees[] = $fee;
$added_fee = $fee;
$added_fee['action'] = 'add';
$this->pending['fees'][] = $added_fee;
reset($this->fees);
$this->increase_fees($fee['amount']);
return true;
}