input: Write a function to determine if two given strings are anagrams, i.e., they contain the same characters in the same frequency. If they 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("tiger", "trigge")==False
  assert is_anagram("", "nonempty")==False
output: def is_anagram(str1, str2):
      if str1 == "" or str2 == "":
          return False
      return sorted(str1) == sorted(str2)