input: Write a function to determine if two strings are anagrams. Two strings are considered anagrams if they contain the same characters with the same frequencies. If the lengths of the two strings are different, they are not anagrams. Return True if they are anagrams, otherwise return False.
  
  def is_anagram(str1, str2):
      if len(str1) != len(str2):
          return False
      
      str1_counts = collections.Counter(str1)
      str2_counts = collections.Counter(str2)
      
      for char in str1_counts:
          if str1_counts[char] != str2_counts[char]:
              return False
      return True
  
  assert is_anagram("abcd", "cbda")==True
  assert is_anagram("listen", "silent")==True
  assert is_anagram("hello", "world")==False
  assert is_anagram("anagram", "nagaram")==True
  assert is_anagram("a", "b")==False
output: 
  def is_anagram(str1, str2):
      if len(str1) != len(str2):
          return False
      
      str1_counts = collections.Counter(str1)
      str2_counts = collections.Counter(str2)
      
      for char in str1_counts:
          if str1_counts[char] != str2_counts[char]:
              return False
      return True
  