core-bundle/src/Resources/contao/library/Contao/Model/Registry.php
public function fetchByAlias($strTable, $strAlias, $varValue)
	{
		if (isset($this->arrAliases[$strTable][$strAlias][$varValue]))
		{
			$strPk = $this->arrAliases[$strTable][$strAlias][$varValue];

			if (isset($this->arrRegistry[$strTable][$strPk]))
			{
				return $this->arrRegistry[$strTable][$strPk];
			}
		}

		return null;
	}
public function fetchByAlias($strTable, $strAlias, $varValue)
	{
		if (isset($this->arrAliases[$strTable][$strAlias][$varValue]))
		{
			$strPk = $this->arrAliases[$strTable][$strAlias][$varValue];

			if (isset($this->arrRegistry[$strTable][$strPk]))
			{
				return $this->arrRegistry[$strTable][$strPk];
			}
		}

		return null;
	}
Fetch a model by one of its aliases

@param string $strTable The table name
@param string $strAlias The alias
@param mixed  $varValue The alias value

@return Model|null The model or null