having tested this on my machine, i dont get any issues. 

Its actually not defined this way in the parent class [here](https://github.com/guzzle/guzzle/blob/master/src/Guzzle/Service/Client.php#L74)

as for the "no parameters issue", it doesnt matter. If no parameters are passed to the function, `$args` will be an empty array. I've also tested that.