input: Write a python function to find the smallest number in a list of integers.
  assert find_smallest([3, 1, 4, 1, 5, 9, 2, 6, 5]) == 1
  assert find_smallest([10, 20, 30, 5, 7, 9]) == 5
  assert find_smallest([50, 22, 13, 49, 58]) == 13
output: def find_smallest(numbers):
      return min(numbers)