def METHOD_NAME(self, p=0):
    h = 0.5
    box = [-h, 1+h, -h, 1+h]
    node = np.array([
        [0.0, 0.0],
        [1.0, 0.0],
        [1.0, 1.0],
        [0.0, 1.0]], dtype=np.float)
    cell = np.array([[1, 2, 0]], dtype=np.int)
    mesh = TriangleMesh(node, cell)
    space = RaviartThomasFiniteElementSpace2d(mesh, p=p)
    fig = plt.figure()
    space.METHOD_NAME(fig, box=box)
    cell = np.array([[3, 0, 2]], dtype=np.int)
    mesh = TriangleMesh(node, cell)
    space = RaviartThomasFiniteElementSpace2d(mesh, p=p)
    fig = plt.figure()
    space.METHOD_NAME(fig, box=box)
    print(space.bcoefs)
    plt.show()