def dmp_diff(f, m, u, K):
    if not u:
        return dup_diff(f, m, K)
    if m <= 0:
        return f

    n = dmp_degree(f, u)

    if n < m:
        return dmp_zero(u)

    deriv, v = [], u - 1

    if m == 1:
        for coeff in f[:-m]:
            deriv.append(dmp_mul_ground(coeff, K(n), v, K))
            n -= 1
    else:
        for coeff in f[:-m]:
            k = n

            for i in range(n - 1, n - m, -1):
                k *= i

            deriv.append(dmp_mul_ground(coeff, K(k), v, K))
            n -= 1

    return dmp_strip(deriv, u)
``m``-th order derivative in ``x_0`` of a polynomial in ``K[X]``.
dataset/ETHPy150Open sympy/sympy/sympy/polys/densetools.py/dmp_diff