input: Write a Python function to check if a number is an Armstrong number.
  assert isArmstrong(371) == True
  assert isArmstrong(9474) == True
  assert isArmstrong(123) == False
output: def isArmstrong(number):
      digits = list(map(int, str(number)))
      power = len(digits)
      total = sum(digit ** power for digit in digits)
      return total == number