Custom error message not working?

[aasiph]

Below is the code

<?php

namespace App\Data;

use DateTime;
use Spatie\LaravelData\Attributes\Validation\Rule;
use Spatie\LaravelData\Data;
use Spatie\TypeScriptTransformer\Attributes\TypeScript;

#[TypeScript]
class MemberData extends Data {
    public ?int $id;
    #[Rule('required|alpha|max:50')]
    public string $first_name;
    #[Rule('required|alpha|max:50')]
    public string $middle_name;
    #[Rule('required|alpha|max:50')]
    public string $last_name;
    #[Rule('required|in:M,F')]
    public string $gender;
    #[Rule('nullable|date_format:Y-m-d|before:today')]
    public ?DateTime $birthdate;
    #[Rule('nullable')]
    public ?string $address;
    #[Rule('nullable|digits:10')]
    public ?string $mobile;

    /**
     * Get the error messages for the defined validation rules.
     * @return array
     */
    public static function messages(): array
    {
        return [
                'gender' => 'Please select a valid gender.'
        ];
    }

    public static function attributes(): array
    {
        return [
                'first_name' => 'First Name',
                'gender' => 'Gender',
        ];
    }
}

The value for gender should be M or F. If null or any other character then above message should be displayed. But it displays the default error as shown in the image below. I can see the attributes are working perfect.

[aasiph]

Never mind adding dot * worked..

/**
     * Get the error messages for the defined validation rules.
     * @return array
     */
    public static function messages(): array
    {
        return [
                'gender.*' => 'Please select a valid gender.',
                'first_name.required' => 'Just for required',
                'first_name.*' => 'General error message',
        ];
    }