input: Write a python function to create a dictionary mapping each string to its length in a list.
  assert string_length_dictionary(["apple", "banana", "cherry"]) == {"apple": 5, "banana": 6, "cherry": 6}
  assert string_length_dictionary(["a", "ab", "abc"]) == {"a": 1, "ab": 2, "abc": 3}
  assert string_length_dictionary(["", " ", "  "]) == {"": 0, " ": 1, "  ": 2}
output: def string_length_dictionary(strings):
      return {s: len(s) for s in strings}