Coloring question (Python)

Title: Divide a circle into a small, n-shaped fan that marks these sectors as three-to-three,..., N. Each sector is now painted with M-color, and each sector is painted in one color, and the adjacent fan color is different, how many different kinds of coating are asked? (n≥1,m≥3)

Ref: 79529355

Recursive resolution:

When N=1 is, f (1,m) = m
When N=2 is, f (1,m) = m (m-1)
When N=3 is, f (1,m) = m (m-1) (m-2)
When N=4, f (4,m) = m (m-1) (m-2) (m-2) + M (m-1) (m-1) = m (m-1) (m^2-3m+3)
When N=5, f (5,m) = m (m-1) (m-2) (m-2) + M (m-1) (m-1) (m-1) = m (m-1) (m^2-3m+3) (m-1) = f (4,m) (m-1)
Can eject relationship f (n,m) = f (n-1,m) (m-1)

def calculate(n,m):    """    :param n: n个扇形    :param m: m种颜色    :return: 涂法的种类    """    if n == 1:        return m    if n == 2:        return m * (m-1)    if n == 3:        return m * (m-1) * (m-2)    if n == 4:        return m * (m-1) * (m-2) * (m-2) + m * (m-1) * (m-1)    return calculate(n-1,m) * (m-1)print(calculate(4,4))

Coloring question (Python)