input: Write a python function to sort a list of strings by their length in descending order.
  assert sort_list(["cat", "dog", "elephant", "tiger"]) == ["elephant", "tiger", "dog", "cat"]
  assert sort_list(["a", "ab", "abc", "abcd"]) == ["abcd", "abc", "ab", "a"]
  assert sort_list(["apple", "banana", "cherry", "date"]) == ["banana", "cherry", "apple", "date"]
output: def sort_list(strings):
      return sorted(strings, key=len, reverse=True)