input: Write a function to sort a given list of names alphabetically. If the list is empty, it should return an empty list.
  def sort_names(names):
      if not names:
          return []
      names.sort()
      return names
  
  assert sort_names(["John", "Harry", "Robert"])==["Harry", "John", "Robert"]
  assert sort_names(["Alice", "Bob", "Charlie"])==["Alice", "Bob", "Charlie"]
  assert sort_names([])==[]
  assert sort_names(["Zoe", "Yvonne", "Xavier"])==["Xavier", "Yvonne", "Zoe"]
output: def sort_names(names):
      if not names:
          return []
      names.sort()
      return names