Check a participants data.

def data_check(self, participant):
        """Check a participants data."""
        participant_id = participant.uniqueid

        nodes = Node.query.filter_by(participant_id=participant_id).all()

        if len(nodes) != self.experiment_repeats + self.practice_repeats:
            print("Error: Participant has {} nodes. Data check failed"
                  .format(len(nodes)))
            return False

        nets = [n.network_id for n in nodes]
        if len(nets) != len(set(nets)):
            print "Error: Participant participated in the same network \
                   multiple times. Data check failed"
            return False

        if None in [n.fitness for n in nodes]:
            print "Error: some of participants nodes are missing a fitness. \
                   Data check failed."
            return False

        if None in [n.score for n in nodes]:
            print "Error: some of participants nodes are missing a score. \
                   Data check failed"
            return False
        return True