input: Write a python function to determine if a number is a perfect cube and if so, find its cube root.
  assert cube_root(27) == 3
  assert cube_root(-8) == -2
  assert cube_root(25) == "Not a perfect cube"
output: def cube_root(n):
      if n < 0:
          cube_root = round(abs(n) ** (1/3)) * -1
      else:
          cube_root = round(n ** (1/3))
      if cube_root ** 3 == n:
          return cube_root
      else:
          return "Not a perfect cube"