input: from typing import List
  
  def smallestNumber(nums: List[int]) -> int:
      """Find the smallest number in the given list.
      >>> smallestNumber([4, 5, 6, 7, 8])
      4
      """
output:     if not nums:
          return None
      smallest = nums[0]
      for num in nums:
          if num < smallest:
              smallest = num
      return smallest