def __init__(self, x_left=0, y_top=0, x_right=0, y_bottom=0):
    self.xl = x_left
    self.yt = y_top
    self.xr = x_right
    self.yb = y_bottom
def __init__(self, x_left=0, y_top=0, x_right=0, y_bottom=0):
    self.xl = x_left
    self.yt = y_top
    self.xr = x_right
    self.yb = y_bottom