lib/catissue/migration/migrator.rb
def clear(target)
      pcl = target_protocol(target) || return
      logger.debug { "Clearing #{pcl.qp} CPR and SCG references..." }
      @database.lazy_loader.suspend do
        pcl.registrations.clear
        pcl.events.each { |event| event.specimen_collection_groups.clear }
      end
    end
def clear(target)
      pcl = target_protocol(target) || return
      logger.debug { "Clearing #{pcl.qp} CPR and SCG references..." }
      @database.lazy_loader.suspend do
        pcl.registrations.clear
        pcl.events.each { |event| event.specimen_collection_groups.clear }
      end
    end
Clears the migration protocol CPR and SCG references.
 This action frees up memory for the next iteration, thereby ensuring that migration is an
 O(1) rather than O(n) operation.