error with relationship

Repeater::make('purchaseBrands')
                    ->relationship()
                    ->schema([
                        Select::make('brand_id')
                            ->label('Brand')
                            ->relationship('brand', 'name', function (Builder $query, Get $get) {
                                if($get('../../supplier_id') === null) {
                                    return;
                                }
                                $brandIds = Supplier::find($get('../../supplier_id'))->brand_id;
                                $query->whereIn('id', $brandIds);
                            })
                            ->searchable()
                            ->disableOptionsWhenSelectedInSiblingRepeaterItems()
                    ->required()
                            ->preload()
                            ->createOptionForm([
                                TextInput::make('name')
                                    ->required()
                                    ->label('New Brand'),
                                TextInput::make('brand_amount')
                                    ->numeric()
                                    ->required()
                            ]),
                        TextInput::make('amount')->required()
                            ->required(),
                    ])