def fixity_check
      results = file_set.files.collect { |f| fixity_check_file(f) }

      return if async_jobs

      results.flatten.group_by(&:file_id)
    end
def fixity_check
      results = file_set.files.collect { |f| fixity_check_file(f) }

      return if async_jobs

      results.flatten.group_by(&:file_id)
    end
@param file_set [ActiveFedora::Base, String] file_set
 @param async_jobs [Boolean] Run actual fixity checks in background. Default true.
 @param max_days_between_fixity_checks [int] if an exisitng fixity check is
   recorded within this window, no new one will be created. Default
   `Hyrax.config.max_days_between_fixity_checks`. Set to -1 to force
    check.
 @param latest_version_only [Booelan]. Check only latest version instead of all
   versions. Default false.
 Fixity checks each version of each file if it hasn't been checked recently
 If object async_jobs is false, will returns the set of most recent fixity check
 status for each version of the content file(s). As a hash keyed by file_id,
 values arrays of possibly multiple version checks.

 If async_jobs is true (default), just returns nil, stuff is still going on.