filtering with different filters for every query

[jeffwillette]

I was playing around with the filter kwarg, and found that the kwarg will only accept a single function as a filter, whereas the knn_query will accept a vector of queries. It may be the case that we want to apply a different filter to each query, something like this...

queries = np.random.normal(size=(128, 8))
idx, dists = hnswlib.knn_query(queries, k=16, filter=[lambda idx: idx < i for i in range(128)]

Is this something which should be supported internally in the lib? Or should I just use pythons map() to make different knn_queries for each filter function?