core-bundle/src/Resources/contao/library/Contao/Model/Collection.php
public function save()
	{
		if ($this->intIndex < 0)
		{
			$this->first();
		}

		$this->arrModels[$this->intIndex]->save();

		return $this;
	}
public function save()
	{
		if ($this->intIndex < 0)
		{
			$this->first();
		}

		$this->arrModels[$this->intIndex]->save();

		return $this;
	}
Save the current model

@return static The model collection object