def load_file
        file_reference = params[:file]
        return default_file unless file_reference

        file_path = Hyrax::DerivativePath.derivative_path_for_reference(params[asset_param_key], file_reference)
        File.exist?(file_path) ? file_path : nil
      end
def load_file
        file_reference = params[:file]
        return default_file unless file_reference

        file_path = Hyrax::DerivativePath.derivative_path_for_reference(params[asset_param_key], file_reference)
        File.exist?(file_path) ? file_path : nil
      end
Overrides Hydra::Controller::DownloadBehavior#load_file, which is hard-coded to assume files are in BasicContainer.
 Override this method to change which file is shown.
 Loads the file specified by the HTTP parameter `:file`.
 If this object does not have a file by that name, return the default file
 as returned by {#default_file}
 @return [ActiveFedora::File, File, NilClass] Returns the file from the repository or a path to a file on the local file system, if it exists.