input: Write a python function to check if a number is an Armstrong number.
  assert checkArmstrong(153) == '153 is an Armstrong Number'
  assert checkArmstrong(9474) == '9474 is an Armstrong Number'
  assert checkArmstrong(370) == '370 is an Armstrong Number'
  assert checkArmstrong(123) == '123 is not an Armstrong Number'
output: def checkArmstrong(n):
      num_str = str(n)
      num_len = len(num_str)
      sum_of_powers = sum(int(digit) ** num_len for digit in num_str)
      if sum_of_powers == n:
          return f'{n} is an Armstrong Number'
      else:
          return f'{n} is not an Armstrong Number'