input: Write a python function to print numbers divisible by three from 0 to n.
  assert print_divisible_by_three(10) == "0 3 6 9 "
  assert print_divisible_by_three(20) == "0 3 6 9 12 15 18 "
  assert print_divisible_by_three(5) == "0 3 "
output: def print_divisible_by_three(n):
      result = ""
      for i in range(n + 1):
          if i % 3 == 0:
              result += str(i) + " "
      return result