Accessors and Mutators in Laravel 5.3

Question

How do I run my own method in Accessors and Mutators of Laravel 5.3 it works with the methods of PHP itself, but if I try to use a method of my own, it gives error.

I’ve tried it like this:

public function getUsuTelefoneAttribute($value) {
    $generalInfo = new GeneralInfo();
    $this->attributes['usu_telefone'] = $generalInfo->masc_tel($value);
}

and tried so:

public function getUsuTelefoneAttribute($value, GeneralInfo $generalInfo) {
    $this->attributes['usu_telefone'] = $generalInfo->masc_tel($value);
}

but both make a mistake