throw error if period start is not set
throw error if period start is not set

pmattmann/ecamp3,usu/ecamp3,ecamp/ecamp3,ecamp/ecamp3,usu/ecamp3,pmattmann/ecamp3,pmattmann/ecamp3,ecamp/ecamp3,usu/ecamp3,usu/ecamp3,pmattmann/ecamp3,ecamp/ecamp3