how can i make mot with run_video.py

Hi, thanks for this repo. i tried to make MOT with the TaMOs when using run_video.py.But it seems that i can only track a single obj.I tried to fix it by switch the parameter bellow which do no help in the end.

```
class TaMOs(BaseTracker):

    multiobj_mode = os.environ.get('MULTIOBJ_MODE', 'parallel')

```
does mot really works?or i coding the wrong parameter?
thanks,