run demo.py encounter bug

[sneepbob]

Hello, how can I solve this bug？:)

command: python demo.py circledet --arch hourglass --demo ../docs/demo.png --load_model ../models/circledet_monuseg_hg.pth

debug:
Traceback (most recent call last):
File "E:/Pycharm_Project/Circle_detection/CircleNet-master/src/demo.py", line 11, in
from lib.detectors.detector_factory import detector_factory
File "E:\Pycharm_Project\Circle_detection\CircleNet-master\src\lib\detectors\detector_factory.py", line 5, in
from .exdet import ExdetDetector
File "E:\Pycharm_Project\Circle_detection\CircleNet-master\src\lib\detectors\exdet.py", line 15, in
from external.nms import soft_nms
ModuleNotFoundError: No module named 'external.nms'

environment: windows10+python3.8+torch1.10+cython0.29.24