code: def match_filtered_identities(self, fa, fb):
          
          if not isinstance(fa, GitHubUsernameIdentity):
              raise ValueError("<fa> is not an instance of GitHubUsernameIdentity")
          if not isinstance(fb, GitHubUsernameIdentity):
              raise ValueError("<fb> is not an instance of GitHubUsernameIdentity")
  
          if fa.uuid and fb.uuid and fa.uuid == fb.uuid:
              return True
  
          if self._check_blacklist(fa):
              return False
  
          # Compare username
          return fa.username and (fa.username == fb.username)
docs: Determine if two filtered identities are the same.
  
          This method compares the username and the source of each
          identity to check if the given unique identities are the
          same. Identities sources have to start with 'github' keyword
          (uppercase or lowercase). When the given filtered identities
          are the same object or share the same UUID, this will also
          produce a positive match.
  
          Identities which their usernames 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 EmailNameIdentity class.