input: 
  def sort_ascending(nums):
      """
      Sorts a list of integers in ascending order using the selection sort algorithm.
      >>> sort_ascending([4, 2, 1, 3])
      [1, 2, 3, 4]
      >>> sort_ascending([5, 2, 9, 1, 5, 6])
      [1, 2, 5, 5, 6, 9]
      >>> sort_ascending([7, 7, 7, 7, 7])
      [7, 7, 7, 7, 7]
      """
      for i in range(len(nums)):
          min_idx = i
          for j in range(i + 1, len(nums)):
              if nums[min_idx] > nums[j]:
                  min_idx = j
          nums[i], nums[min_idx] = nums[min_idx], nums[i] 
      return nums
  
output:     for i in range(len(nums)):
          min_idx = i
          for j in range(i + 1, len(nums)):
              if nums[min_idx] > nums[j]:
                  min_idx = j
          nums[i], nums[min_idx] = nums[min_idx], nums[i] 
      return nums