When using open3d, normal visualization can be performed after the point cloud is established, but it involves calculation, such as calling estimate_ Normals or o3d.pipelines.registration.registration_ ICP, an error segmentation fault (core dumped) will be reported

Solution: import open3d as O3D at the beginning（ It seems that the reference order of some packages will affect open3d.)

# Here are my codes below:
pc_pre=o3d.geometry.PointCloud()  
pc_cur=o3d.geometry.PointCloud()
pc_pre.points=o3d.utility.Vector3dVector(pre_cloud)
pc_cur.points=o3d.utility.Vector3dVector(cur_cloud)
res=o3d.pipelines.registration.registration_icp(source=pc_cur,target=pc_pre,
        max_correspondence_distance=threshold)
print(res)