input: Write a function that takes an array as input and prints it out backwards. If the array is empty, print "Array is empty". If the given array is empty then return None.
  assert print_reverse_array([1, 2, 3, 4, 5])==None
  assert print_reverse_array([5, 4, 3, 2, 1])==None
  assert print_reverse_array([7, 8, 9, 10])==None
  assert print_reverse_array([])==None
output: def print_reverse_array(arr):
      if not arr:
          print("Array is empty")
      else:
          for i in range(len(arr)-1, -1, -1):
              print(arr[i])