Error: argmax(): argument 'input' (position 1) must be Tensor, not str

Hi,
I followed your guide, but it displayed the error _'argmax(): argument 'input' (position 1) must be Tensor, not str_' as in the screenshot above.
Actually, when I tried to print the 'start_scores' and 'end_scores', they are actually the string, start_score = "start_logits" and end_scores = 'end_logits'
Could you please help to check?

Thanks