message: Make the visualization tool handle null shape gracefully.
diff: @@ -202,7 +202,7 @@ class TensorMapper(object):
  html += str(i) + " "
  html += tensor["name"] + " "
  html += str(tensor["type"]) + " "
  - html += repr(tensor["shape"]) + "<br>"
  + html += (repr(tensor["shape"]) if "shape" in tensor else "[]") + "<br>"
  html += "</span>"
  html += repr(x)
  html += "</span>"
  