BUG: fixed error with accessing next and previous submissions
BUG: fixed error with accessing next and previous submissions

ksurya/SciPyCentral,ksurya/SciPyCentral,Srisai85/SciPyCentral,ksurya/SciPyCentral,scipy/SciPyCentral,scipy/SciPyCentral,Srisai85/SciPyCentral,wqshi/test,Srisai85/SciPyCentral,scipy/SciPyCentral,wqshi/test,wqshi/test