Hi, I'm very new to processing and I was just trying to do something simple.
I'm wondering if I could get some help?
When I run this, I get a tiny screen, instead of the bigger screen I'm supposed to get, does anyone know why? I also don't get a white background either...
Each class/interface has it's own tab, please help, thank you!

class Main implements Drawable {
private Gui _gui;
public void setup(){
_gui = new Gui(600,400);
}
public void draw(){
  _gui.draw();
}
}

interface Drawable {
  void draw();
}

class Gui implements Drawable {
  color _bgcolor = (color(255));
  public Gui(int width, int height) {
    size(width, height);
}
void draw() {
  background(this._bgcolor);
}
}


Even if you have no idea what's wrong, a reply would be appreciated so I know it's not just me @_@