title: visual studio code error: Cannot read property 'then' of undefined
body: <p>I have installed visual studio code in my centos7 system plus python and jupyter extensions, then I tried to do a simply test like: 3+2 in vs code by using jupyter extension. It shows me such error:
  <strong>Cannot read property 'then' of undefined</strong>
  I really have no idea about this problem. Could someone do me a favor? Thanks a million!</p>
  <p>Sihan</p>