input: 
  def find_smallest_number(numbers):
      smallest = numbers[0] 
      for num in numbers:
          if num < smallest:
              smallest = num
      return smallest
  
  # Example:
  # >>> find_smallest_number([5, 4, 12, 17, 9])
  # 4
  
output:     for num in numbers:
          if num < smallest:
              smallest = num
      return smallest