code: public static function findByPk($varValue, array $arrOptions=array())
  	{
  		// Try to load from the registry
  		if (empty($arrOptions))
  		{
  			$objModel = Registry::getInstance()->fetch(static::$strTable, $varValue);
  
  			if ($objModel !== null)
  			{
  				return $objModel;
  			}
  		}
  
  		$arrOptions = array_merge
  		(
  			array
  			(
  				'limit'  => 1,
  				'column' => static::$strPk,
  				'value'  => $varValue,
  				'return' => 'Model'
  			),
  
  			$arrOptions
  		);
  
  		return static::find($arrOptions);
  	}
docs: Find a single record by its primary key
  
  @param mixed $varValue   The property value
  @param array $arrOptions An optional options array
  
  @return static The model or null if the result is empty