input: Write a python function to check if a number is divisible by 3 and 5.
  assert is_divisible_by_3_and_5(15) == True
  assert is_divisible_by_3_and_5(30) == True
  assert is_divisible_by_3_and_5(10) == False
  assert is_divisible_by_3_and_5(9) == False
output: def is_divisible_by_3_and_5(n):
      return n % 3 == 0 and n % 5 == 0