Observing error when upgrade clojure to 1.9.0 or higher

[shivgana]

When we upgrade clojure to 1.9.0 or higher, and compile, getting

java.io.NotSerializableException: sparkling.broadcast.proxy$org.apache.spark.broadcast.Broadcast$IDeref$e595a7c1

Reference to error on code line:

sparkling/src/clojure/sparkling/broadcast.clj

Line 5 in 2870dbd

(clojure.lang IDeref)

Please convert parenthesis to square branch on referring "clojure.lang IDeref"