message: There are .tflite files that are missing some metadata (at least description).
  With this change visualize.py can process those files.
diff: @@ -334,7 +334,7 @@ def CreateHtmlFile(tflite_input, html_output):
  for key, mapping in toplevel_stuff:
  if not mapping:
  mapping = lambda x: x
  - html += "<tr><th>%s</th><td>%s</td></tr>\n" % (key, mapping(data[key]))
  + html += "<tr><th>%s</th><td>%s</td></tr>\n" % (key, mapping(data.get(key)))
  html += "</table>\n"
  # Spec on what keys to display
  