StoreModel array unique validation

my_model.rb

class MyModel
  attribute :my_array_of_store_models, MyStoreModel.to_array_type, default: -> { [] }
  validates :my_array_of_store_models,
            store_model: true,
            "store_model_validators/unique": { attrs: [:name] }
end

my_store_model.rb

class MyStoreModel
  include StoreModel::Model
  attribute :name, :string
  validates :name, presence: true
end

store_model_validators__unique_validator.rb

class StoreModelValidatators::UniqueValidator < ActiveModel::EachValidator
  def validate_each(record, attribute, value)
    options[:attrs].each do |validated_attribute|
      AttributeUniqueValidatorInstance.new(
        record:,
        collection_attribute: attribute,
        collection: value,
        attribute: validated_attribute
      ).validate
    end
  end

  class AttributeUniqueValidatorInstance
    def initialize(record:, collection_attribute:, collection:, attribute:)
      @record = record
      @collection_attribute = collection_attribute
      @collection = collection
      @attribute = attribute
    end

    def validate
      add_duplicate_error if duplicate_attribute_values.any?
    end

    private

    def duplicate_attribute_values
      all_attribute_values
        .select { |value| all_attribute_values.count(value) > 1 }
        .uniq
    end

    def all_attribute_values = @collection.pluck(@attribute)

    def add_duplicate_error
      message = "can't contain duplicate #{@attribute}s (duplicates: #{duplicate_attribute_values.join(', ')})"
      @record.errors.add(@collection_attribute, error_type, message:)
    end

    def error_type = :"duplicate_#{@attribute}"
  end
end