Check a participant paid attention.

def attention_check(self, participant=None):
        """Check a participant paid attention."""
        participant_nodes = Node.query.join(Node.network)\
            .filter(and_(Node.participant_id == participant.uniqueid,
                         Network.role == "catch"))\
            .all()
        scores = [n.score for n in participant_nodes]

        if participant_nodes:
            avg = sum(scores) / float(len(scores))
        else:
            return True

        is_passing = avg >= self.min_acceptable_performance
        return is_passing