Class 'Brick\Math\BigDecimal' not found

[muath-ic]

I am using laravel and when I send sms I got this error
Symfony \ Component \ Debug \ Exception \ FatalThrowableError (E_ERROR) Class 'Brick\Math\BigDecimal' not found

The SMS message sent but with internal server error 500 so this make problems with my API client

I tried to fix it by myself but I did not find the class Brick\Math\BigDecimal in this class ObjectSerializer here is the link to the line which I mean https://github.com/karixtech/karix-php/blob/v2/lib/ObjectSerializer.php#L32

and the problem occurs at this line of code https://github.com/karixtech/karix-php/blob/v2/lib/ObjectSerializer.php#L268

I hope I get solution of my problem!