code: public function getVariantBase()
      {
          if ($this->getMetaModel()->hasVariants() && !$this->isVariantBase()) {
              return $this->getMetaModel()->findById($this->get('vargroup'));
          }
  
          return $this;
      }
docs: Fetch the meta model variant base for this item.
  
  Note: For a non-variant item the variant base is the item itself.
  
  @return IItem The variant base.