public function addArg($arg, $desc = '', $required = false) { if (array_key_exists($arg, $this->_args)) { $interface = PS_CLI_INTERFACE::getInterfaceInstance(); $interface->add_warning("argument {$arg} has already been defined"); } $this->_args[$arg] = array('description' => $desc, 'required' => $required); return $this; }