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