input: Write a function to determine if two strings are anagrams of each other. If they are, return True; otherwise, return False. If either or both strings are empty, return False.
  assert is_anagram("abcd", "cbda") == True
  assert is_anagram("silent", "listen") == True
  assert is_anagram("hello", "world") == False
  assert is_anagram("", "test") == False
  assert is_anagram("", "") == False
output: def is_anagram(s1, s2):
      if not s1 or not s2:
          return False
      return sorted(s1) == sorted(s2)