src/RawPHP/RawSupport/Collection/Collection.php
protected function getGroupByKey( $group, $key, $value )
    {
        if ( !is_string( $group ) && is_callable( $group ) )
        {
            return $group( $value, $key );
        }

        return Util::dataGet( $value, $group );
    }
protected function getGroupByKey( $group, $key, $value )
    {
        if ( !is_string( $group ) && is_callable( $group ) )
        {
            return $group( $value, $key );
        }

        return Util::dataGet( $value, $group );
    }
protected function getGroupByKey ( $ group , $ key , $ value ) { if ( ! is_string ( $ group ) && is_callable ( $ group ) ) { return $ group ( $ value , $ key ) ; } return Util :: dataGet ( $ value , $ group ) ; }
Get the 'group by' key value.

@param Closure|string $group
@param string         $key
@param mixed          $value

@return string
Get the group by key value .