input: def sort_ascending(nums):
      """ Sort a list of integers in ascending order using selection sort.
      >>> sort_ascending([3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5])
      [1, 1, 2, 3, 3, 4, 5, 5, 5, 6, 9]
      >>> sort_ascending([6, 4, 2, 1, 3, 5])
      [1, 2, 3, 4, 5, 6]
      """
      for i in range(len(nums)):
output:     min_index = i
      for j in range(i + 1, len(nums)):
          if nums[j] < nums[min_index]:
              min_index = j
      nums[i], nums[min_index] = nums[min_index], nums[i]
  return nums