```ruby
class AssetManager::AttachmentUpdater::ReplacementIdUpdates
  def self.call(attachment_data)
    return [] unless attachment_data.replaced?

    replacement = attachment_data.replaced_by

    Enumerator.new do |enum|
      enum.yield AssetManager::AttachmentUpdater::Update.new(
        attachment_data, attachment_data.file, replacement_legacy_url_path: replacement.file.asset_manager_path
      )

      if attachment_data.pdf?
        if replacement.pdf?
          enum.yield AssetManager::AttachmentUpdater::Update.new(
            attachment_data, attachment_data.file.thumbnail, replacement_legacy_url_path: replacement.file.thumbnail.asset_manager_path
          )
        else
          enum.yield AssetManager::AttachmentUpdater::Update.new(
            attachment_data, attachment_data.file.thumbnail, replacement_legacy_url_path: replacement.file.asset_manager_path
          )
        end
      end
    end
  end
end
```

Refactor the ReplacementIdUpdates class for readability
user
```ruby
class AssetManager::AttachmentUpdater::ReplacementIdUpdates
  def self.call(attachment_data)
    return [] unless attachment_data.replaced?

    replacement = attachment_data.replaced_by

    Enumerator.new do |enum|
      enum.yield(
        AssetManager::AttachmentUpdater::Update.new(
          attachment_data,
          attachment_data.file,
          replacement_legacy_url_path: replacement.file.asset_manager_path,
        ),
      )

      if attachment_data.pdf?
        replacement_legacy_url_path = if replacement.pdf?
                                        replacement.file.thumbnail.asset_manager_path
                                      else
                                        replacement.file.asset_manager_path
                                      end
        enum.yield(
          AssetManager::AttachmentUpdater::Update.new(
            attachment_data,
            attachment_data.file.thumbnail,
            replacement_legacy_url_path: replacement_legacy_url_path,
          ),
        )
      end
    end
  end
end
```
assistant