run test_RFB.py error

[Damon2019]

i run the run test_RFB.py .An error occurred

im_detect: 761/1000 0.024s 0.020s
im_detect: 781/1000 0.020s 0.015s
im_detect: 801/1000 0.019s 0.014s
im_detect: 821/1000 0.020s 0.017s
im_detect: 841/1000 0.024s 0.017s
im_detect: 861/1000 0.019s 0.013s
im_detect: 881/1000 0.019s 0.013s
im_detect: 901/1000 0.019s 0.013s
im_detect: 921/1000 0.019s 0.014s
im_detect: 941/1000 0.019s 0.013s
im_detect: 961/1000 0.019s 0.012s
im_detect: 981/1000 0.019s 0.012s
Evaluating detections
Writing ship VOC results file
VOC07 metric? Yes
Traceback (most recent call last):
File "test_RFB.py", line 193, in
top_k, thresh=0.01)
File "test_RFB.py", line 144, in test_net
testset.evaluate_detections(all_boxes, save_folder)
File "/home/huangf/github/RFBNet/data/voc0712.py", line 256, in evaluate_detections
self._do_python_eval(output_dir)
File "/home/huangf/github/RFBNet/data/voc0712.py", line 313, in _do_python_eval
use_07_metric=use_07_metric)
File "/home/huangf/github/RFBNet/data/voc_eval.py", line 130, in voc_eval
R = [obj for obj in recs[imagename] if obj['name'] == classname]
KeyError: '000506'

Can someone help me?,thank you!