def match_filtered_identities(self, fa, fb):
        """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.
        """
        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
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.