Submission trouble

I met a submission trouble, and the stderr file show:
Traceback (most recent call last):
File “/code/scripts/workers/submission_worker.py”, line 426, in run_submission
submission_metadata=submission_serializer.data,
File “/tmp/tmp2p8ajy6s/compute/challenge_data/challenge_454/main.py”, line 109, in evaluate
outputs[k] = eval_forecasting.compute_forecasting_metrics(output,gt,city_dict,k,30,2,prob)
File “/code/argoverse-api/argoverse/evaluation/eval_forecasting.py”, line 195, in compute_forecasting_metrics
metric_results[“DAC”] = get_drivable_area_compliance(forecasted_trajectories, city_names, max_n_guesses)
File “/code/argoverse-api/argoverse/evaluation/eval_forecasting.py”, line 154, in get_drivable_area_compliance
city_name = city_names[seq_id]
KeyError: 8928

Why does ‘8928’ have a key error?