python: Fix assert
python: Fix assert

should work in the case num_data == 1 and batch_size == 1

kevinthesun/mxnet,ykim362/mxnet,coder-james/mxnet,szha/mxnet,hesseltuinhof/mxnet,jennyzhang0215/incubator-mxnet,szha/mxnet,larroy/mxnet,luoyetx/mxnet,stefanhenneking/mxnet,Northrend/mxnet,jiajiechen/mxnet,yuruofeifei/mxnet,sergeykolychev/mxnet,TuSimple/mxnet,smolix/incubator-mxnet,xcgoner/dist-mxnet,EvanzzzZ/mxnet,nicklhy/mxnet,TuSimple/mxnet,zhreshold/mxnet,yuruofeifei/mxnet,likelyzhao/mxnet,reminisce/mxnet,sxjscience/mxnet,arank/mxnet,szha/mxnet,xcgoner/dist-mxnet,vikingMei/mxnet,luoyetx/mxnet,vikingMei/mxnet,mbaijal/incubator-mxnet,tlby/mxnet,arank/mxnet,smolix/incubator-mxnet,hotpxl/mxnet,xcgoner/dist-mxnet,leezu/mxnet,Northrend/mxnet,DR08/mxnet,ForkedReposBak/mxnet,rahul003/mxnet,solin319/incubator-mxnet,gautamkmr/incubator-mxnet,mbaijal/incubator-mxnet,piiswrong/mxnet,reminisce/mxnet,crazy-cat/incubator-mxnet,ZihengJiang/mxnet,EvanzzzZ/mxnet,stefanhenneking/mxnet,jamesliu/mxnet,precedenceguo/mxnet,Prasad9/incubator-mxnet,sergeykolychev/mxnet,arikpoz/mxnet,gautamkmr/incubator-mxnet,hpi-xnor/BMXNet,ShownX/incubator-mxnet,Mega-DatA-Lab/mxnet,TuSimple/mxnet,pluskid/mxnet,navrasio/mxnet,kkk669/mxnet,stefanhenneking/mxnet,hpi-xnor/BMXNet,hpi-xnor/BMXNet,arank/mxnet,apaleyes/mxnet,gautamkmr/incubator-mxnet,coder-james/mxnet,indhub/mxnet,Ldpe2G/mxnet,sxjscience/mxnet,ykim362/mxnet,solin319/incubator-mxnet,precedenceguo/mxnet,szha/mxnet,larroy/mxnet,weleen/mxnet,LinkHS/incubator-mxnet,thirdwing/mxnet,tornadomeet/mxnet,hpi-xnor/BMXNet,leezu/mxnet,zhreshold/mxnet,yuruofeifei/mxnet,DR08/mxnet,tlby/mxnet,stefanhenneking/mxnet,LinkHS/incubator-mxnet,jiajiechen/mxnet,stefanhenneking/mxnet,mbaijal/incubator-mxnet,weleen/mxnet,jermainewang/mxnet,vikingMei/mxnet,arank/mxnet,sergeykolychev/mxnet,larroy/mxnet,smolix/incubator-mxnet,solin319/incubator-mxnet,luoyetx/mxnet,wangyum/mxnet,jennyzhang0215/incubator-mxnet,TuSimple/mxnet,xcgoner/dist-mxnet,LinkHS/incubator-mxnet,jiajiechen/mxnet,gautamkmr/incubator-mxnet,Prasad9/incubator-mxnet,mbaijal/incubator-mxnet,xcgoner/dist-mxnet,sergeykolychev/mxnet,formath/mxnet,wangyum/mxnet,kkk669/mxnet,fullfanta/mxnet,Guneet-Dhillon/mxnet,lxn2/mxnet,ZihengJiang/mxnet,tornadomeet/mxnet,Ldpe2G/mxnet,dmlc/mxnet,saurabh3949/mxnet,smolix/incubator-mxnet,crazy-cat/incubator-mxnet,nicklhy/mxnet,Northrend/mxnet,DR08/mxnet,rishita/mxnet,DR08/mxnet,rishita/mxnet,madjam/mxnet,wangyum/mxnet,crazy-cat/incubator-mxnet,dmlc/mxnet,Ldpe2G/mxnet,madjam/mxnet,yuruofeifei/mxnet,dmlc/mxnet,coder-james/mxnet,Northrend/mxnet,nicklhy/mxnet,coder-james/mxnet,ykim362/mxnet,sergeykolychev/mxnet,jamesliu/mxnet,Mega-DatA-Lab/mxnet,sxjscience/mxnet,kevinthesun/mxnet,smolix/incubator-mxnet,jermainewang/mxnet,likelyzhao/mxnet,larroy/mxnet,yajiedesign/mxnet,antoan2/incubator-mxnet,indhub/mxnet,xcgoner/dist-mxnet,navrasio/mxnet,pluskid/mxnet,CodingCat/mxnet,jennyzhang0215/incubator-mxnet,CodingCat/mxnet,antoan2/incubator-mxnet,jermainewang/mxnet,coder-james/mxnet,leezu/mxnet,precedenceguo/mxnet,vikingMei/mxnet,EvanzzzZ/mxnet,tornadomeet/mxnet,nicklhy/mxnet,navrasio/mxnet,sxjscience/mxnet,piiswrong/mxnet,Mega-DatA-Lab/mxnet,rahul003/mxnet,stefanhenneking/mxnet,szha/mxnet,jamesliu/mxnet,Ldpe2G/mxnet,likelyzhao/mxnet,dmlc/mxnet,Guneet-Dhillon/mxnet,solin319/incubator-mxnet,hpi-xnor/BMXNet,coder-james/mxnet,rahul003/mxnet,Northrend/mxnet,hotpxl/mxnet,apache/incubator-mxnet,lxn2/mxnet,EvanzzzZ/mxnet,ykim362/mxnet,jamesliu/mxnet,piiswrong/mxnet,hotpxl/mxnet,larroy/mxnet,Guneet-Dhillon/mxnet,ForkedReposBak/mxnet,luoyetx/mxnet,tlby/mxnet,madjam/mxnet,hesseltuinhof/mxnet,madjam/mxnet,lxn2/mxnet,weleen/mxnet,weleen/mxnet,jamesliu/mxnet,arank/mxnet,Northrend/mxnet,EvanzzzZ/mxnet,fullfanta/mxnet,dmlc/mxnet,lxn2/mxnet,apaleyes/mxnet,ykim362/mxnet,apache/incubator-mxnet,ShownX/incubator-mxnet,likelyzhao/mxnet,DR08/mxnet,hpi-xnor/BMXNet,arikpoz/mxnet,likelyzhao/mxnet,saurabh3949/mxnet,sergeykolychev/mxnet,apaleyes/mxnet,kkk669/mxnet,ForkedReposBak/mxnet,rishita/mxnet,pluskid/mxnet,jamesliu/mxnet,piiswrong/mxnet,yajiedesign/mxnet,piiswrong/mxnet,pluskid/mxnet,jermainewang/mxnet,Guneet-Dhillon/mxnet,ForkedReposBak/mxnet,hotpxl/mxnet,crazy-cat/incubator-mxnet,tlby/mxnet,wangyum/mxnet,jamesliu/mxnet,zhreshold/mxnet,rishita/mxnet,jennyzhang0215/incubator-mxnet,dmlc/mxnet,wangyum/mxnet,yuruofeifei/mxnet,coder-james/mxnet,Prasad9/incubator-mxnet,TuSimple/mxnet,weleen/mxnet,solin319/incubator-mxnet,smolix/incubator-mxnet,hpi-xnor/BMXNet,arikpoz/mxnet,sergeykolychev/mxnet,likelyzhao/mxnet,danithaca/mxnet,dmlc/mxnet,wangyum/mxnet,rishita/mxnet,formath/mxnet,mbaijal/incubator-mxnet,lxn2/mxnet,antoan2/incubator-mxnet,ForkedReposBak/mxnet,mbaijal/incubator-mxnet,thirdwing/mxnet,jennyzhang0215/incubator-mxnet,ZihengJiang/mxnet,reminisce/mxnet,yajiedesign/mxnet,Mega-DatA-Lab/mxnet,Ldpe2G/mxnet,ptrendx/mxnet,Northrend/mxnet,sergeykolychev/mxnet,kevinthesun/mxnet,coder-james/mxnet,navrasio/mxnet,fullfanta/mxnet,ShownX/incubator-mxnet,CodingCat/mxnet,reminisce/mxnet,CodingCat/mxnet,leezu/mxnet,kkk669/mxnet,indhub/mxnet,rahul003/mxnet,gautamkmr/incubator-mxnet,apaleyes/mxnet,jiajiechen/mxnet,solin319/incubator-mxnet,ShownX/incubator-mxnet,kkk669/mxnet,jennyzhang0215/incubator-mxnet,ShownX/incubator-mxnet,ForkedReposBak/mxnet,Prasad9/incubator-mxnet,crazy-cat/incubator-mxnet,stefanhenneking/mxnet,piiswrong/mxnet,sxjscience/mxnet,stefanhenneking/mxnet,hotpxl/mxnet,jermainewang/mxnet,sxjscience/mxnet,rahul003/mxnet,solin319/incubator-mxnet,Prasad9/incubator-mxnet,tlby/mxnet,yajiedesign/mxnet,pluskid/mxnet,arikpoz/mxnet,vikingMei/mxnet,eric-haibin-lin/mxnet,ShownX/incubator-mxnet,formath/mxnet,LinkHS/incubator-mxnet,zhreshold/mxnet,TuSimple/mxnet,Mega-DatA-Lab/mxnet,eric-haibin-lin/mxnet,yuruofeifei/mxnet,yuruofeifei/mxnet,jamesliu/mxnet,apaleyes/mxnet,formath/mxnet,hesseltuinhof/mxnet,jiajiechen/mxnet,EvanzzzZ/mxnet,arikpoz/mxnet,jiajiechen/mxnet,Mega-DatA-Lab/mxnet,danithaca/mxnet,CodingCat/mxnet,jermainewang/mxnet,lxn2/mxnet,kkk669/mxnet,piiswrong/mxnet,fullfanta/mxnet,navrasio/mxnet,ptrendx/mxnet,Ldpe2G/mxnet,tlby/mxnet,apache/incubator-mxnet,LinkHS/incubator-mxnet,apaleyes/mxnet,kkk669/mxnet,smolix/incubator-mxnet,weleen/mxnet,precedenceguo/mxnet,gautamkmr/incubator-mxnet,TuSimple/mxnet,jiajiechen/mxnet,yuruofeifei/mxnet,danithaca/mxnet,DickJC123/mxnet,thirdwing/mxnet,thirdwing/mxnet,szha/mxnet,mbaijal/incubator-mxnet,reminisce/mxnet,rishita/mxnet,smolix/incubator-mxnet,CodingCat/mxnet,saurabh3949/mxnet,tornadomeet/mxnet,apaleyes/mxnet,ptrendx/mxnet,xcgoner/dist-mxnet,thirdwing/mxnet,saurabh3949/mxnet,thirdwing/mxnet,precedenceguo/mxnet,indhub/mxnet,tlby/mxnet,tlby/mxnet,vikingMei/mxnet,apache/incubator-mxnet,pluskid/mxnet,hpi-xnor/BMXNet,yajiedesign/mxnet,reminisce/mxnet,kkk669/mxnet,smolix/incubator-mxnet,luoyetx/mxnet,leezu/mxnet,larroy/mxnet,Northrend/mxnet,mbaijal/incubator-mxnet,ForkedReposBak/mxnet,ZihengJiang/mxnet,pluskid/mxnet,xcgoner/dist-mxnet,leezu/mxnet,gautamkmr/incubator-mxnet,tornadomeet/mxnet,saurabh3949/mxnet,jiajiechen/mxnet,apaleyes/mxnet,formath/mxnet,wangyum/mxnet,jermainewang/mxnet,stefanhenneking/mxnet,navrasio/mxnet,vikingMei/mxnet,arank/mxnet,CodingCat/mxnet,thirdwing/mxnet,leezu/mxnet,indhub/mxnet,ykim362/mxnet,ForkedReposBak/mxnet,thirdwing/mxnet,saurabh3949/mxnet,Prasad9/incubator-mxnet,antoan2/incubator-mxnet,wangyum/mxnet,indhub/mxnet,jamesliu/mxnet,hesseltuinhof/mxnet,zhreshold/mxnet,luoyetx/mxnet,vikingMei/mxnet,kevinthesun/mxnet,danithaca/mxnet,sxjscience/mxnet,weleen/mxnet,ptrendx/mxnet,weleen/mxnet,piiswrong/mxnet,precedenceguo/mxnet,eric-haibin-lin/mxnet,Ldpe2G/mxnet,nicklhy/mxnet,crazy-cat/incubator-mxnet,eric-haibin-lin/mxnet,apaleyes/mxnet,pluskid/mxnet,luoyetx/mxnet,hesseltuinhof/mxnet,EvanzzzZ/mxnet,antoan2/incubator-mxnet,arikpoz/mxnet,fullfanta/mxnet,CodingCat/mxnet,arikpoz/mxnet,mbaijal/incubator-mxnet,eric-haibin-lin/mxnet,coder-james/mxnet,ykim362/mxnet,gautamkmr/incubator-mxnet,ptrendx/mxnet,ptrendx/mxnet,ptrendx/mxnet,yajiedesign/mxnet,arikpoz/mxnet,hesseltuinhof/mxnet,larroy/mxnet,Mega-DatA-Lab/mxnet,reminisce/mxnet,Mega-DatA-Lab/mxnet,TuSimple/mxnet,madjam/mxnet,eric-haibin-lin/mxnet,szha/mxnet,precedenceguo/mxnet,sergeykolychev/mxnet,fullfanta/mxnet,crazy-cat/incubator-mxnet,precedenceguo/mxnet,hotpxl/mxnet,solin319/incubator-mxnet,zhreshold/mxnet,DR08/mxnet,sxjscience/mxnet,tornadomeet/mxnet,ykim362/mxnet,Guneet-Dhillon/mxnet,nicklhy/mxnet,nicklhy/mxnet,hesseltuinhof/mxnet,Northrend/mxnet,tornadomeet/mxnet,hesseltuinhof/mxnet,ZihengJiang/mxnet,danithaca/mxnet,ykim362/mxnet,ZihengJiang/mxnet,Prasad9/incubator-mxnet,likelyzhao/mxnet,vikingMei/mxnet,LinkHS/incubator-mxnet,sxjscience/mxnet,luoyetx/mxnet,navrasio/mxnet,arank/mxnet,arikpoz/mxnet,pluskid/mxnet,Guneet-Dhillon/mxnet,ShownX/incubator-mxnet,ShownX/incubator-mxnet,fullfanta/mxnet,rishita/mxnet,antoan2/incubator-mxnet,ZihengJiang/mxnet,tornadomeet/mxnet,DickJC123/mxnet,yajiedesign/mxnet,arank/mxnet,rahul003/mxnet,Prasad9/incubator-mxnet,wangyum/mxnet,rishita/mxnet,LinkHS/incubator-mxnet,lxn2/mxnet,rishita/mxnet,hpi-xnor/BMXNet,solin319/incubator-mxnet,larroy/mxnet,DickJC123/mxnet,leezu/mxnet,nicklhy/mxnet,Ldpe2G/mxnet,eric-haibin-lin/mxnet,hotpxl/mxnet,ZihengJiang/mxnet,hotpxl/mxnet,jermainewang/mxnet,zhreshold/mxnet,zhreshold/mxnet,szha/mxnet,rahul003/mxnet,DR08/mxnet,weleen/mxnet,Mega-DatA-Lab/mxnet,ptrendx/mxnet,yuruofeifei/mxnet,madjam/mxnet,precedenceguo/mxnet,fullfanta/mxnet,formath/mxnet,ForkedReposBak/mxnet,kevinthesun/mxnet,arank/mxnet,rahul003/mxnet,jiajiechen/mxnet,danithaca/mxnet,gautamkmr/incubator-mxnet,LinkHS/incubator-mxnet,TuSimple/mxnet,lxn2/mxnet,reminisce/mxnet,kevinthesun/mxnet,Ldpe2G/mxnet,antoan2/incubator-mxnet,dmlc/mxnet,piiswrong/mxnet,indhub/mxnet,larroy/mxnet,rahul003/mxnet,hotpxl/mxnet,Guneet-Dhillon/mxnet,navrasio/mxnet,thirdwing/mxnet,yajiedesign/mxnet,DR08/mxnet,danithaca/mxnet,indhub/mxnet,eric-haibin-lin/mxnet,saurabh3949/mxnet,DickJC123/mxnet,formath/mxnet,eric-haibin-lin/mxnet,LinkHS/incubator-mxnet,likelyzhao/mxnet,luoyetx/mxnet,crazy-cat/incubator-mxnet,jennyzhang0215/incubator-mxnet,tlby/mxnet,kevinthesun/mxnet,tornadomeet/mxnet,likelyzhao/mxnet,zhreshold/mxnet,danithaca/mxnet,Guneet-Dhillon/mxnet,formath/mxnet,ZihengJiang/mxnet,reminisce/mxnet,danithaca/mxnet,saurabh3949/mxnet,indhub/mxnet,TuSimple/mxnet,ptrendx/mxnet,madjam/mxnet,madjam/mxnet,Guneet-Dhillon/mxnet,ptrendx/mxnet,reminisce/mxnet,leezu/mxnet,navrasio/mxnet,jennyzhang0215/incubator-mxnet,tlby/mxnet,hesseltuinhof/mxnet,ShownX/incubator-mxnet,dmlc/mxnet,DR08/mxnet,Prasad9/incubator-mxnet,EvanzzzZ/mxnet,kkk669/mxnet,crazy-cat/incubator-mxnet,yajiedesign/mxnet,jennyzhang0215/incubator-mxnet,antoan2/incubator-mxnet,jermainewang/mxnet,kevinthesun/mxnet,saurabh3949/mxnet,nicklhy/mxnet,CodingCat/mxnet,madjam/mxnet,fullfanta/mxnet,szha/mxnet,lxn2/mxnet,antoan2/incubator-mxnet,EvanzzzZ/mxnet,formath/mxnet,kevinthesun/mxnet,xcgoner/dist-mxnet