input: def sort_ascending(nums):
      """
      Sort a list of integers in ascending order using selection sort algorithm.
      
      >>> sort_ascending([4, 3, 2, 1])
      [1, 2, 3, 4]
      >>> sort_ascending([36, 24, 52, 11, 48, 7])
      [7, 11, 24, 36, 48, 52]
      >>> sort_ascending([])
      []
      >>> sort_ascending([1])
      [1]
      >>> sort_ascending([5, 5, 5, 5])
      [5, 5, 5, 5]
      """
output:     for i in range(len(nums)):
          min_idx = i
          for j in range(i+1, len(nums)):
              if nums[j] < nums[min_idx]:
                  min_idx = j
          nums[i], nums[min_idx] = nums[min_idx], nums[i]
      return nums