input: Write a function to find the smallest number in a list of numbers. Return the smallest number found.
  def find_smallest_number(numbers):
      smallest = numbers[0] 
      for num in numbers:
          if num < smallest:
              smallest = num
      return smallest
  
  print(find_smallest_number([5, 4, 12, 17, 9]))
  assert find_smallest_number([5, 4, 12, 17, 9])==4
  assert find_smallest_number([7, 3, 9, 6, 1])==1
  assert find_smallest_number([10, 10, 10, 10])==10
  assert find_smallest_number([-5, 0, 3, -8, 2])==-8
  assert find_smallest_number([1])==1
output: def find_smallest_number(numbers):
      smallest = numbers[0] 
      for num in numbers:
          if num < smallest:
              smallest = num
      return smallest