OrderBy sets the optional parameter "orderBy": The ordering of the returned list. The only supported value are placedDate desc and placedDate asc for now, which returns orders sorted by placement date. "placedDate desc" stands for listing orders by placement date, from oldest to most recent. "placedDate asc" stands for listing orders by placement date, from most recent to oldest. In future releases we'll support other sorting criteria.
"placedDate asc" "placedDate desc"