input: Write a python function to sort a list of strings in alphabetical order.
  assert sort_strings(['banana', 'apple', 'orange']) == ['apple', 'banana', 'orange']
  assert sort_strings(['dog', 'cat', 'bird']) == ['bird', 'cat', 'dog']
  assert sort_strings(['zebra', 'monkey', 'lion']) == ['lion', 'monkey', 'zebra']
output: def sort_strings(strings):
      return sorted(strings)