public function addSkillReference(ChildSkillReference $l)
    {
        if ($this->collSkillReferences === null) {
            $this->initSkillReferences();
            $this->collSkillReferencesPartial = true;
        }

        if (!$this->collSkillReferences->contains($l)) {
            $this->doAddSkillReference($l);
        }

        return $this;
    }