wrapper for nullable attribute
wrapper for nullable attribute

Reviewed By: yfeldblum

Differential Revision: D2784472

fb-gh-sync-id: 84c7426cc82edabb04c662fa699764ffc0864b7e

sonnyhu/folly,mqeizi/folly,sonnyhu/folly,Hincoin/folly,brunomorishita/folly,mqeizi/folly,floxard/folly,charsyam/folly,floxard/folly,facebook/folly,brunomorishita/folly,rklabs/folly,mqeizi/folly,sonnyhu/folly,charsyam/folly,floxard/folly,charsyam/folly,mqeizi/folly,Orvid/folly,Hincoin/folly,brunomorishita/folly,Orvid/folly,Orvid/folly,Hincoin/folly,brunomorishita/folly,sonnyhu/folly,Orvid/folly,rklabs/folly,mqeizi/folly,facebook/folly,rklabs/folly,rklabs/folly,Hincoin/folly,floxard/folly,rklabs/folly,Orvid/folly,sonnyhu/folly,facebook/folly,charsyam/folly,Hincoin/folly,brunomorishita/folly,floxard/folly,facebook/folly,facebook/folly