input: Write a function to sort a list of strings alphabetically. If the input list is empty, return an empty list.
  assert sort_strings(["Hello", "Yes", "No", "World"])==["Hello", "No", "World", "Yes"]
  assert sort_strings(["Apple", "Banana", "Cherry"])==["Apple", "Banana", "Cherry"]
  assert sort_strings([])==[]
  assert sort_strings(["Zebra"])==["Zebra"]
output: def sort_strings(lst):
      return sorted(lst)