input: Write a function to determine if two given strings are anagrams, meaning they contain the same characters in the same frequency. If they are anagrams, return True; otherwise, return False. If either string is empty, return False.
  assert is_anagram("abcd", "cbda")==True
  assert is_anagram("hello", "world")==False
  assert is_anagram("anagram", "nagaram")==True
  assert is_anagram("", "non-empty")==False
  assert is_anagram("python", "typhon")==True
output: def is_anagram(s1, s2):
      if s1 == "" or s2 == "":
          return False
      return sorted(s1) == sorted(s2)