Fix lint-python errors

Author: Lewuathe

python/pyspark/mllib/regression.py

@@ -135,7 +135,7 @@ def _regression_train_wrapper(train_func, modelClass, data, initial_weights):
     first = data.first()
     if not isinstance(first, LabeledPoint):
         raise ValueError("data should be an RDD of LabeledPoint, but got %s" % first)
-    if initial_weights == None:
+    if initial_weights is None:
         initial_weights = [0.0] * len(data.first().features)
     weights, intercept = train_func(data, _convert_to_vector(initial_weights))
     return modelClass(weights, intercept)

python/pyspark/mllib/tests.py

@@ -330,6 +330,7 @@ def test_regression(self):
         except ValueError:
             self.fail()
 
+
 class StatTests(PySparkTestCase):
     # SPARK-4023
     def test_col_with_different_rdds(self):