input: from typing import List
  
  def lengths_of_strings(strings: List[str]) -> List[int]:
      """ Given a list of strings, return a list of their lengths.
      >>> lengths_of_strings(["apple", "banana", "cherry"])
      [5, 6, 6]
      >>> lengths_of_strings(["hello", "world", ""])
      [5, 5, 0]
      """
output:     return [len(s) for s in strings]