code: def match_filtered_identities(self, fa, fb):
          
          if not isinstance(fa, UsernameIdentity):
              raise ValueError("<fa> is not an instance of UsernameIdentity")
          if not isinstance(fb, UsernameIdentity):
              raise ValueError("<fb> is not an instance of UsernameIdentity")
  
          if fa.uuid and fb.uuid and fa.uuid == fb.uuid:
              return True
  
          if fa.username in self.blacklist:
              return False
  
          # Compare username first
          if fa.username and fa.username == fb.username:
              return True
  
          return False
docs: Determine if two filtered identities are the same.
  
          The method compares the username of each filtered identity
          to check if they are the same. When the given filtered identities
          are the same object or share the same UUID, this will also
          produce a positive match.
  
          Identities which their username are in the blacklist will be
          ignored and the result of the comparison will be false.
  
          :param fa: filtered identity to match
          :param fb: filtered identity to match
  
          :returns: True when both filtered identities are likely to be the same.
              Otherwise, returns False.
  
          :raises ValueError: when any of the given filtered identities is not
              an instance of UsernameIdentity class.