input: Write a function to sort a list of strings based on their length. If the list is empty, return the empty list.
  assert sort_strings_by_length(["Hello","World!","Good","Morning"])==["Good","Hello","Morning","World!"]
  assert sort_strings_by_length(["Python","Java","C++","Ruby"])==["C++","Java","Ruby","Python"]
  assert sort_strings_by_length(["a","is","to","go"])==["a","is","to","go"]
  assert sort_strings_by_length([])==[]
  assert sort_strings_by_length(["one"])==["one"]
output: def sort_strings_by_length(strings):
      return sorted(strings, key=len)