input: Write a function to check if two given strings are anagrams. If the two strings are anagrams, return True; otherwise, return False. If either of the strings is empty, return False.
  
  assert is_anagram("abcd", "cbda")==True
  assert is_anagram("listen", "silent")==True
  assert is_anagram("hello", "world")==False
  assert is_anagram("abc", "ab")==False
  assert is_anagram("", "test")==False
  assert is_anagram("test", "")==False
output: def is_anagram(s1, s2):
      if not s1 or not s2:
          return False
      return sorted(s1) == sorted(s2)