input: Write a python function to sort a list of integers in ascending order using selection sort.
  assert sort_list([8, 15, 2, 18, 10]) == [2, 8, 10, 15, 18]
  assert sort_list([5, 3, 8, 6, 2]) == [2, 3, 5, 6, 8]
  assert sort_list([1, 2, 3, 4, 5]) == [1, 2, 3, 4, 5]
output: def sort_list(arr):
      n = len(arr)
      for i in range(n):
          min_index = i
          for j in range(i+1, n):
              if arr[j] < arr[min_index]:
                  min_index = j
          arr[i], arr[min_index] = arr[min_index], arr[i]
      return arr