fix flow error [skip ci]
fix flow error [skip ci]

claudiopro/babel,babel/babel,maurobringolf/babel,jridgewell/babel,PolymerLabs/babel,kaicataldo/babel,Skillupco/babel,hzoo/babel,babel/babel,kedromelon/babel,claudiopro/babel,claudiopro/babel,vadzim/babel,guybedford/babel,kellyselden/babel,existentialism/babel,kellyselden/babel,kellyselden/babel,jridgewell/babel,kaicataldo/babel,existentialism/babel,vadzim/babel,shuhei/babel,kedromelon/babel,kellyselden/babel,Skillupco/babel,shuhei/babel,guybedford/babel,PolymerLabs/babel,samwgoldman/babel,maurobringolf/babel,maurobringolf/babel,guybedford/babel,hulkish/babel,babel/babel,existentialism/babel,kaicataldo/babel,Skillupco/babel,PolymerLabs/babel,chicoxyzzy/babel,chicoxyzzy/babel,chicoxyzzy/babel,kaicataldo/babel,chicoxyzzy/babel,babel/babel,samwgoldman/babel,kedromelon/babel,hzoo/babel,shuhei/babel,hulkish/babel,hulkish/babel,hzoo/babel,samwgoldman/babel,hulkish/babel,Skillupco/babel,jridgewell/babel,jridgewell/babel,hzoo/babel