input: Write a Python function to divide an array into two parts and move the first segment to the end.
  assert rearrange_Arr([12,10,5,6,52,36],6,2) == [5,6,52,36,12,10]
  assert rearrange_Arr([1,2,3,4],4,1) == [2,3,4,1]
  assert rearrange_Arr([0,1,2,3,4,5,6,7],8,3) == [3,4,5,6,7,0,1,2]
output: def rearrange_Arr(arr, n, k):
      return arr[k:] + arr[:k]