'usage: getbbox
Push left, upper, right, and lower pixel coordinates of the top image.'

def do_getbbox(self):

    bounding_box = self.do_pop().getbbox()
    self.push(bounding_box[3])
    self.push(bounding_box[2])
    self.push(bounding_box[1])
    self.push(bounding_box[0])
