Init estimation for regression. (#8272)

tests/test_distributed/test_with_spark/test_spark_local_cluster.py

@@ -1,7 +1,6 @@
 import json
 import os
 import random
-import sys
 import uuid
 
 import numpy as np
@@ -216,7 +215,7 @@ class XgboostLocalClusterTestCase(SparkLocalClusterTestCase):
             ],
         )
         self.reg_best_score_eval = 5.239e-05
-        self.reg_best_score_weight_and_eval = 4.810e-05
+        self.reg_best_score_weight_and_eval = 4.850e-05
 
     def test_regressor_basic_with_params(self):
         regressor = SparkXGBRegressor(**self.reg_params)

tests/test_distributed/test_with_spark/utils.py

@@ -4,16 +4,15 @@ import shutil
 import sys
 import tempfile
 import unittest
+from io import StringIO
 
 import pytest
-from six import StringIO
 
 from xgboost import testing as tm
 
 pytestmark = [pytest.mark.skipif(**tm.no_spark())]
 
-
-from pyspark.sql import SparkSession, SQLContext
+from pyspark.sql import SparkSession
 from xgboost.spark.utils import _get_default_params_from_func