public function argument(?string $key = null)
    {
        if ($key === null) {
            return $this->input->getArguments();
        }

        return $this->input->getArgument($key);
    }
public function argument(?string $key = null)
    {
        if ($key === null) {
            return $this->input->getArguments();
        }

        return $this->input->getArgument($key);
    }
public function argument ( ? string $ key = null ) { if ( $ key === null ) { return $ this -> input -> getArguments ( ) ; } return $ this -> input -> getArgument ( $ key ) ; }
Get the value of a command argument.

@param null|string $key

@return null|array|string
Get the value of a command argument .