input: Write a python function to sort an array of strings alphabetically.
  assert alphabetical_sort(["cat", "elephant", "dog", "bird"]) == ["bird", "cat", "dog", "elephant"]
  assert alphabetical_sort(["banana", "apple", "cherry"]) == ["apple", "banana", "cherry"]
  assert alphabetical_sort(["zebra", "giraffe", "lion", "tiger"]) == ["giraffe", "lion", "tiger", "zebra"]
output: def alphabetical_sort(arr):
      return sorted(arr)