Add new Attribute to select filter

[JulitoM3]

Im trying to add a new attribute to select filter, im following the docs in the livewire-powergrid configuration but its not working

/*
    |--------------------------------------------------------------------------
    | Filters Attributes
    |--------------------------------------------------------------------------

    | You can add custom attributes to the filters.
    | The key is the filter type and the value is a callback function.
    | like: input_text, select, datetime, etc.
    | The callback function receives the field and title as parameters.
    | The callback function must return an array with the attributes.
    */

    'filter_attributes' => [
        'input_text' => \PowerComponents\LivewirePowerGrid\FilterAttributes\InputText::class,
        'boolean' => \PowerComponents\LivewirePowerGrid\FilterAttributes\Boolean::class,
        'number' => \PowerComponents\LivewirePowerGrid\FilterAttributes\Number::class,
        'select' => function ($field, $title) {
            return [
                'class' => \PowerComponents\LivewirePowerGrid\FilterAttributes\Select::class,
                'attributes' => [
                    'data-step-capturista-6',
                    'data-intro' => "Aquí puedes filtrar por' . $title",
                ],
            ];
        },

it gives me this error

Object of class Closure could not be converted to string.

What am i missing?