public function filterBySkillReference($skillReference, $comparison = null)
    {
        if ($skillReference instanceof \gossi\trixionary\model\SkillReference) {
            return $this
                ->addUsingAlias(SkillTableMap::COL_ID, $skillReference->getSkillId(), $comparison);
        } elseif ($skillReference instanceof ObjectCollection) {
            return $this
                ->useSkillReferenceQuery()
                ->filterByPrimaryKeys($skillReference->getPrimaryKeys())
                ->endUse();
        } else {
            throw new PropelException('filterBySkillReference() only accepts arguments of type \gossi\trixionary\model\SkillReference or Collection');
        }
    }