SpatialKNN support of non-point geometry in  candidates side ?

Does the SpatialKNN algorithm support using non-point geometries for CandidatesFeatureCol? 
I am trying to test this use case, but it is not working. I want to confirm whether this issue is due to SpatialKNN not supporting non-point geometries in the CandidatesFeatureCol.
FYI, i am using also a non-point geometry on landmarks side.
Thank you.