def getTopLeft(self):
        """
        Retrieves a tuple with the x,y coordinates of the upper left point of the circle. 
        Requires the radius and the coordinates to be numbers
        """
        return (float(self.get_cx()) - float(self.get_r()), float(self.get_cy()) + float(self.get_r()))
Retrieves a tuple with the x,y coordinates of the upper left point of the circle. 
        Requires the radius and the coordinates to be numbers