input: Write a function to take a list of strings as input and print the strings in alphabetical order. If the input list is empty, print "No strings to sort". The function should return None.
  assert sort_strings(['cat', 'dog', 'apple', 'banana'])==None
  assert sort_strings(['zebra', 'apple', 'mango', 'banana'])==None
  assert sort_strings([])==None
  assert sort_strings(['apple'])==None
output: def sort_strings(lst):
      if lst:
          for s in sorted(lst):
              print(s)
      else:
          print("No strings to sort")
      return None