pickling error while doing joblib, or numba

I get a
TypeError: can't pickle open3d.open3d.geometry.PointCloud objects
when I try to parallelize a for loop to (multiple) query the KDTree.
I have tried joblib and numba and both give me same error.

my code is basically
```def myfunc(i):
[k, idx, _] = pcd_tree.search_knn_vector_3d(pcd.points[i], 1000)
return idx
results = Parallel(n_jobs=num_cores, verbose=50)(delayed(
myfunc)(i)for i in my_list)
```

Is there an alternate fast method for multiple querying the KD Tree?

Thanks!