input: Write a python function to sort a list of integers based on the sum of their digits.
  assert sortBySumOfDigits([135, 590, 69, 127]) == [127, 135, 69, 590]
  assert sortBySumOfDigits([98, 45, 26, 73]) == [26, 45, 73, 98]
  assert sortBySumOfDigits([301, 120, 405, 222]) == [120, 301, 222, 405]
output: def sortBySumOfDigits(lst):
      return sorted(lst, key=lambda x: sum(int(digit) for digit in str(x)))