/** * Returns the absolute value of a number. * * The <number> argument can be any valid expression as long as it resolves * to a number. * * @see https://docs.mongodb.org/manual/reference/operator/aggregation/abs/ * @see Expr::abs * @param mixed|Expr $number * @return self * * @since 1.3 */ public function abs($number) { $this->expr->abs($number); return $this; }