input: Write a function to sort a list of strings by their lengths.
  assert sort_list_by_length(["Python", "is", "a", "programming", "language"])==["a", "is", "Python", "language", "programming"]
  assert sort_list_by_length(["short", "medium", "longest", "tiny"])==["tiny", "short", "medium", "longest"]
  assert sort_list_by_length(["apple", "pie", "banana", "cherry"])==["pie", "apple", "banana", "cherry"]
output: def sort_list_by_length(lst):
      return sorted(lst, key=len)