input: from typing import List
  
  def sort_by_length(strings: List[str]) -> List[str]:
      """
      Sorts a list of strings based on their length.
      
      >>> sorted_list = sort_by_length(["Hello", "World!", "Good", "Morning"])
      >>> print(sorted_list)
      ["Good", "Hello", "Morning", "World!"]
      """
      strings.sort(key=len)
      return strings
output:     return strings