>>> df = spark.createDataFrame([(25,),(35,)], ["n"])
>>> df.selectExpr("n", "bround(n, -1) as bround_n").show()
+---+--------+
|  n|bround_n|
+---+--------+
| 25|      20|
| 35|      40|
+---+--------+

>>> df = spark.createDataFrame([(25.0,),(35.0,)], ["n"])
>>> df.selectExpr("n", "bround(n, -1) as bround_n").show()
+----+--------+
|   n|bround_n|
+----+--------+
|25.0|    20.0|
|35.0|    40.0|
+----+--------+
