'kd Tree' With Custom Distance Metric

I want to use 'KDtree'(this is the best option. Other 'KNN' algorithms aren't optimal for my project) with custom distance metric. I checked some answers here for similar questions

Solution 1:

Scikit-learn's KDTree does not support custom distance metrics. The BallTree does support custom distance metrics, but be careful: it is up to the user to make certain the provided metric is actually a valid metric: if it is not, the algorithm will happily return results of a query, but the results will be incorrect.

Also, you should be aware that using a custom Python function as a metric is generally too slow to be useful, because of the overhead of Python callbacks within the traversal of the tree.