input: Write a function to determine if it is possible to get an array sorted in non-decreasing order by performing any number of right shift operations on the given array. If it is possible return True else return False. If the given array is empty then return True.
  assert find_max([1, 15, 20, 6])==20
  assert find_max([5, 8, 10, 20, 7])==20
  assert find_max([-1, -5, -3, -2])==-1
  assert find_max([10])==10
  assert find_max([])==None
output: def can_be_sorted_by_shifts(arr):
      if not arr:
          return True
      n = len(arr)
      count = 0
      for i in range(1, n):
          if arr[i] < arr[i-1]:
              count += 1
      return count <= 1