code: def Kn2Der(nu, y, n=0):
      r
      n = int(n)
      y = scipy.asarray(y, dtype=float)
      sqrty = scipy.sqrt(y)
      if n == 0:
          K = scipy.special.kv(nu, sqrty)
      else:
          K = scipy.zeros_like(y)
          x = scipy.asarray(
              [
                  fixed_poch(1.5 - j, j) * y**(0.5 - j)
                  for j in scipy.arange(1.0, n + 1.0, dtype=float)
              ]
          ).T
          for k in scipy.arange(1.0, n + 1.0, dtype=float):
              K += (
                  scipy.special.kvp(nu, sqrty, n=int(k)) *
                  incomplete_bell_poly(n, int(k), x)
              )
      return K
docs: r"""Find the derivatives of :math:`K_\nu(y^{1/2})`.
      
      Parameters
      ----------
      nu : float
          The order of the modified Bessel function of the second kind.
      y : array of float
          The values to evaluate at.
      n : nonnegative int, optional
          The order of derivative to take.