input: Write a python function to find the first 5 numbers that are divisible by 7 but not a multiple of 5.
  assert find_numbers() == [7, 14, 21, 28, 42]
output: def find_numbers():
      result = []
      num = 1
      while len(result) < 5:
          if num % 7 == 0 and num % 5 != 0:
              result.append(num)
          num += 1
      return result