AssertionError: top_pool_forward miss in module _ext while executingpython demo/pcd_demo.py ${PCD_FILE} ${CONFIG_FILE} ${CHECKPOINT_FILE} [--device ${GPU_ID}] [--score-thr ${SCORE_THR}] [--out-dir ${OUT_DIR}]

[eyabesbes]

I have downloaded the dockerfile and I have built the docker image and run it.
Then I have tried to test an example using a demo but I don't know why I keep getting this error:

Traceback (most recent call last):
  File "demo/pcd_demo.py", line 3, in <module>
    from mmdet3d.apis import inference_detector, init_detector, show_result_meshlab
  File "/mmdetection3d/BEVFusion/mmdet3d/apis/__init__.py", line 1, in <module>
    from .inference import (convert_SyncBN, inference_detector, init_detector,
  File "/mmdetection3d/BEVFusion/mmdet3d/apis/inference.py", line 8, in <module>
    from mmdet3d.core import Box3DMode, show_result
  File "/mmdetection3d/BEVFusion/mmdet3d/core/__init__.py", line 1, in <module>
    from .anchor import *  # noqa: F401, F403
  File "/mmdetection3d/BEVFusion/mmdet3d/core/anchor/__init__.py", line 1, in <module>
    from mmdet.core.anchor import build_anchor_generator
  File "/opt/conda/lib/python3.7/site-packages/mmdet/core/__init__.py", line 3, in <module>
    from .bbox import *  # noqa: F401, F403
  File "/opt/conda/lib/python3.7/site-packages/mmdet/core/bbox/__init__.py", line 8, in <module>
    from .samplers import (BaseSampler, CombinedSampler,
  File "/opt/conda/lib/python3.7/site-packages/mmdet/core/bbox/samplers/__init__.py", line 12, in <module>
    from .score_hlr_sampler import ScoreHLRSampler
  File "/opt/conda/lib/python3.7/site-packages/mmdet/core/bbox/samplers/score_hlr_sampler.py", line 3, in <module>
    from mmcv.ops import nms_match
  File "/opt/conda/lib/python3.7/site-packages/mmcv/ops/__init__.py", line 10, in <module>
    from .corner_pool import CornerPool
  File "/opt/conda/lib/python3.7/site-packages/mmcv/ops/corner_pool.py", line 11, in <module>
    'right_pool_forward', 'right_pool_backward'
  File "/opt/conda/lib/python3.7/site-packages/mmcv/utils/ext_loader.py", line 15, in load_ext
    assert hasattr(ext, fun), f'{fun} miss in module {name}'
AssertionError: top_pool_forward miss in module _ext

It seems like I'm having trouble with the mmcv package. So I have downloaded the wheel installation using the following command: pip install mmcv-1.4.0-cp37-cp37m-linux_x86_64.whl
Still, the problem is persistent.