input: Write a function that takes two strings and returns whether they are anagrams. If they are anagrams, return True; otherwise, return False. Two strings are considered anagrams if they contain the same characters in the same frequency, regardless of order. If either of the strings is empty, return False.
  
  assert is_anagram("abcd", "dcba")==True
  assert is_anagram("silent", "listen")==True
  assert is_anagram("hello", "world")==False
  assert is_anagram("aacc", "ccac")==False
  assert is_anagram("", "abc")==False
output: def is_anagram(s1, s2):
      if s1 == "" or s2 == "":
          return False
      return sorted(s1) == sorted(s2)