input: from typing import List
  
  def find_smallest_number(numbers: List[float]) -> float:
      """Find the smallest number in a list of numbers.
      >>> find_smallest_number([5, 4, 12, 17, 9])
      4
      >>> find_smallest_number([15, 7, 23, 10, 4, 8])
      4
      """
output:     if not numbers:
          raise ValueError("The list is empty")
      smallest = numbers[0]
      for number in numbers:
          if number < smallest:
              smallest = number
      return smallest