def _create_circle(self, x, y, r, **kwargs):
    """
    Helper function for easily drawing circles with tkinter, rather than ovals
    :param x: circle centre x-coordinate
    :param y: circle centre y-coordinate
    :param r: circle radius
    :param kwargs:
    :return:
    """
    return self.create_oval(x-r, y-r, x+r, y+r, **kwargs)