/** * Determines if the operand is an array. Returns a boolean. * * The <expression> can be any valid expression. * * @see https://docs.mongodb.org/manual/reference/operator/aggregation/isArray/ * @see Expr::isArray * @param mixed|Expr $expression * @return self * * @since 1.3 */ public function isArray($expression) { $this->expr->isArray($expression); return $this; }