Emits all examples in prolog form for RSD.

            :param pred_name: override for the emitted predicate name

def all_examples(self, pred_name=None):
        '''
        Emits all examples in prolog form for RSD.

            :param pred_name: override for the emitted predicate name
        '''
        target = self.db.target_table
        pred_name = pred_name if pred_name else target
        examples = self.db.rows(target, [self.db.target_att, self.db.pkeys[target]])
        return '\n'.join(["%s(%s, %s)." % (pred_name, ILPConverter.fmt_col(cls), pk) for cls, pk in examples])