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a8bdfa47 - check and then call opt

check and then call opt Summary: Need to check if opt exists before call. Commander diff from Jongsoo. Reviewed By: xuzhao9, yuguo68 Differential Revision: D40372706 fbshipit-source-id: 5f3a9e8edcd2b5b34d87d5015c7300b3920c1a43