input: Write a function to find the smallest number in a given list.
  def smallestNumber(nums):
      smallest = nums[0]
      for i in range(1, len(nums)):
          if nums[i] < smallest:
              smallest = nums[i]
      return smallest
  assert smallestNumber([4, 5, 6, 7, 8]) == 4
  assert smallestNumber([3, 2, 8, 1, 9]) == 1
  assert smallestNumber([9, 8, 7, 6, 5]) == 5
  assert smallestNumber([-1, -2, -3, -4, -5]) == -5
  assert smallestNumber([10]) == 10
output: def smallestNumber(nums):
      smallest = nums[0]
      for i in range(1, len(nums)):
          if nums[i] < smallest:
              smallest = nums[i]
      return smallest