Removes import of unused module.
Removes import of unused module.

aajtodd/zipline,joequant/zipline,enigmampc/catalyst,umuzungu/zipline,keir-rex/zipline,cmorgan/zipline,dmitriz/zipline,michaeljohnbennett/zipline,florentchandelier/zipline,michaeljohnbennett/zipline,kmather73/zipline,Scapogo/zipline,florentchandelier/zipline,humdings/zipline,wilsonkichoi/zipline,dmitriz/zipline,davidastephens/zipline,magne-max/zipline-ja,wubr2000/zipline,chrjxj/zipline,humdings/zipline,gwulfs/zipline,aajtodd/zipline,jordancheah/zipline,kmather73/zipline,iamkingmaker/zipline,joequant/zipline,bartosh/zipline,StratsOn/zipline,YuepengGuo/zipline,bartosh/zipline,mattcaldwell/zipline,morrisonwudi/zipline,ChinaQuants/zipline,dhruvparamhans/zipline,euri10/zipline,ChinaQuants/zipline,erikness/AlephOne,davidastephens/zipline,enigmampc/catalyst,grundgruen/zipline,wubr2000/zipline,nborggren/zipline,CarterBain/AlephNull,alphaBenj/zipline,magne-max/zipline-ja,iamkingmaker/zipline,wilsonkichoi/zipline,stkubr/zipline,sketchytechky/zipline,jimgoo/zipline-fork,keir-rex/zipline,stkubr/zipline,dkushner/zipline,CDSFinance/zipline,morrisonwudi/zipline,otmaneJai/Zipline,nborggren/zipline,jimgoo/zipline-fork,MonoCloud/zipline,StratsOn/zipline,zhoulingjun/zipline,zhoulingjun/zipline,DVegaCapital/zipline,chrjxj/zipline,ronalcc/zipline,grundgruen/zipline,DVegaCapital/zipline,sketchytechky/zipline,alphaBenj/zipline,quantopian/zipline,CarterBain/AlephNull,ronalcc/zipline,Scapogo/zipline,erikness/AlephOne,AlirezaShahabi/zipline,quantopian/zipline,mattcaldwell/zipline,dhruvparamhans/zipline,dkushner/zipline,jordancheah/zipline,umuzungu/zipline,AlirezaShahabi/zipline,semio/zipline,YuepengGuo/zipline,CDSFinance/zipline,euri10/zipline,cmorgan/zipline,gwulfs/zipline,semio/zipline,MonoCloud/zipline,otmaneJai/Zipline