bug72.scala:5: object scala.collection.mutable.Set of type scala.collection.mutable.Set cannot be applied to (java.lang.String,java.lang.String,java.lang.String,java.lang.String,java.lang.String) with expected result type scala.collection.mutable.Set[java.lang.String]
        val weekDays : Set[String] = Set("Mon", "Tue", "Wed", "Thu", "Fri");
                                        ^
one error found