code: def saver_proxy
        # Look for a transfer event that matches the position.
        xfr = specimen.event_parameters.detect do |sep|
          CaTissue::TransferEventParameters === sep and sep.to == location
        end
        # Create a new transfer event, if necessary.
        xfr ||= CaTissue::TransferEventParameters.new(:specimen => specimen, :to => location)
        # If this position changed, then copy the original position to the transfer event from attributes.
        if snapshot and changed? then
          xfr.from_storage_container = snapshot[:storage_container]
          xfr.from_position_dimension_one = snapshot[:position_dimension_one]
          xfr.from_position_dimension_two = snapshot[:position_dimension_two]
        end
        xfr
      end
docs: Returns a TransferEventParameters which serves as a proxy for saving this SpecimenPosition.
  
   @quirk caTissue caTissue does not allow saving a SpecimenPosition directly in the database.
     Creating a TransferEventParameters sets the SpecimenPosition as a side-effect. Therefore,
     SpecimenPosition save is accomplished by creating a proxy TransferEventParameters instead.