public function groupBy($column)
    {
        if (is_null($column)) {
            throw new \InvalidArgumentException('Cannot pass null argument to '.__METHOD__);
        }

        if (is_array($column)) {
            $this->groupBy = $this->extractArrayAttributes($column);

            return $this;
        }

        $this->groupBy = $this->quoteIdentifier($column);

        return $this;
    }