KeyError: 'Non-existent config key: MODEL.FCOS'

[Enternal00]

When I ran the demo.py, I encountered such a problem:

WARNING [11/25 20:08:22 d2.config.compat]: Config 'configs/fcos/fcos_imprv_R_50_FPN.yaml' has no VERSION. Assuming it to be compatible with latest v2.
Traceback (most recent call last):
File "demo/demo.py", line 70, in
cfg = setup_cfg(args)
File "demo/demo.py", line 21, in setup_cfg
cfg.merge_from_file(args.config_file)
File "/home/liuyi/.local/lib/python3.8/site-packages/detectron2/config/config.py", line 54, in merge_from_file
self.merge_from_other_cfg(loaded_cfg)
File "/home/liuyi/.local/lib/python3.8/site-packages/fvcore/common/config.py", line 132, in merge_from_other_cfg
return super().merge_from_other_cfg(cfg_other)
File "/home/liuyi/.local/lib/python3.8/site-packages/yacs/config.py", line 217, in merge_from_other_cfg
_merge_a_into_b(cfg_other, self, self, [])
File "/home/liuyi/.local/lib/python3.8/site-packages/yacs/config.py", line 478, in _merge_a_into_b
_merge_a_into_b(v, b[k], root, key_list + [k])
File "/home/liuyi/.local/lib/python3.8/site-packages/yacs/config.py", line 491, in _merge_a_into_b
raise KeyError("Non-existent config key: {}".format(full_key))
KeyError: 'Non-existent config key: MODEL.FCOS'

Thank you very much for each suggestion.

[PrakharPrashantSingh]

same error!!