auto cast threshold from Integer to Float in approxSimilarityJoin of BucketedRandomProjectionLSHModel

when I was using 

// code placeholder
BucketedRandomProjectionLSHModel.approxSimilarityJoin(dt_features, dt_features, distCol="EuclideanDistance", threshold=20.)

I was confused then that this method reported an exception some java method (dataset, dataset, integer, string) fingerprint can not be found.... I think if I give an integer, and the python method of pyspark should be auto-cast this to float if needed.