make lint-python happy for python3

Author: advancedxy

python/pyspark/sql/utils.py

@@ -18,6 +18,9 @@
 import py4j
 import sys
 
+if sys.version_info.major >= 3:
+    unicode = str
+
 
 class CapturedException(Exception):
     def __init__(self, desc, stackTrace, cause=None):