Object tracking fails with error

[PrashantSaikia]

After I draw the bounding box on the object I want to track, when I press p again, I get the following error:

Object selected at [(857, 280), (912, 394)]
Object tracked at [{}, {}] 
Traceback (most recent call last):
  File "object-tracker-single.py", line 88, in <module>
    run(source, args["dispLoc"])
  File "object-tracker-single.py", line 60, in run
    print ("Object tracked at [{}, {}] \r").format(pt1, pt2),
AttributeError: 'NoneType' object has no attribute 'format'