input: Write a function to sort a list of tuples based on the second element using a lambda function.
  assert sort_list([(3, 4), (2, 5), (1, 6)])==[(3, 4), (2, 5), (1, 6)]
  assert sort_list([(1, 2), (4, 1), (3, 5)])==[(4, 1), (1, 2), (3, 5)]
  assert sort_list([(10, 2), (5, 3), (2, 1)])==[(2, 1), (10, 2), (5, 3)]
output: def sort_list(lst):
      return sorted(lst, key=lambda x: x[1])