diff --git a/django_spanner/base.py b/django_spanner/base.py
index fcf61a22f8..bdbdbc4de1 100644
--- a/django_spanner/base.py
+++ b/django_spanner/base.py
@@ -17,7 +17,7 @@
 from .introspection import DatabaseIntrospection
 from .operations import DatabaseOperations
 from .schema import DatabaseSchemaEditor
-from django_spanner import USING_DJANGO_3, USING_DJANGO_4
+from django_spanner import USING_DJANGO_3
 
 
 class DatabaseWrapper(BaseDatabaseWrapper):
@@ -130,7 +130,7 @@ def allow_transactions_in_auto_commit(self):
             return self.settings_dict["ALLOW_TRANSACTIONS_IN_AUTO_COMMIT"]
         if USING_DJANGO_3:
             return False
-        if USING_DJANGO_4:
+        else:
             return True
 
     @property
diff --git a/django_spanner/compiler.py b/django_spanner/compiler.py
index ad809e337a..a2175113f7 100644
--- a/django_spanner/compiler.py
+++ b/django_spanner/compiler.py
@@ -39,6 +39,8 @@ def get_combinator_sql(self, combinator, all):
         :returns: A tuple containing SQL statement(s) with some additional
                   parameters.
         """
+        # This method copies the complete code of this overridden method from
+        # Django core and modify it for Spanner by adding one line
         if USING_DJANGO_3:
             features = self.connection.features
             compilers = [
@@ -101,6 +103,8 @@ def get_combinator_sql(self, combinator, all):
             if not parts:
                 raise EmptyResultSet
             combinator_sql = self.connection.ops.set_operators[combinator]
+            # This is the only line that is changed from the Django core
+            # implementation of this method
             combinator_sql += " ALL" if all else " DISTINCT"
             braces = (
                 "({})"
@@ -116,6 +120,9 @@ def get_combinator_sql(self, combinator, all):
                 params.extend(part)
 
             return result, params
+        # As the code of this method has somewhat changed in Django 4.2 core
+        # version, so we are copying the complete code of this overridden method
+        # and modifying it for Spanner
         else:
             features = self.connection.features
             compilers = [
@@ -191,6 +198,8 @@ def get_combinator_sql(self, combinator, all):
             if not parts:
                 raise EmptyResultSet
             combinator_sql = self.connection.ops.set_operators[combinator]
+            # This is the only line that is changed from the Django core
+            # implementation of this method
             combinator_sql += " ALL" if all else " DISTINCT"
             braces = "{}"
             if (
diff --git a/tests/unit/django_spanner/test_operations.py b/tests/unit/django_spanner/test_operations.py
index 197bd56688..a1d87520a3 100644
--- a/tests/unit/django_spanner/test_operations.py
+++ b/tests/unit/django_spanner/test_operations.py
@@ -12,7 +12,7 @@
 from django.db.utils import DatabaseError
 from google.cloud.spanner_dbapi.types import DateStr
 
-from django_spanner import USING_DJANGO_3, USING_DJANGO_4
+from django_spanner import USING_DJANGO_3
 from tests.unit.django_spanner.simple_test import SpannerSimpleTestClass
 import uuid
 
@@ -118,7 +118,7 @@ def test_date_extract_sql(self):
                 self.db_operations.date_extract_sql("week", "dummy_field"),
                 "EXTRACT(isoweek FROM dummy_field)",
             )
-        elif USING_DJANGO_4:
+        else:
             self.assertEqual(
                 self.db_operations.date_extract_sql("week", "dummy_field"),
                 ("EXTRACT(isoweek FROM dummy_field)", None),
@@ -132,7 +132,7 @@ def test_date_extract_sql_lookup_type_dayofweek(self):
                 ),
                 "EXTRACT(dayofweek FROM dummy_field)",
             )
-        elif USING_DJANGO_4:
+        else:
             self.assertEqual(
                 self.db_operations.date_extract_sql(
                     "dayofweek", "dummy_field"
@@ -149,7 +149,7 @@ def test_datetime_extract_sql(self):
                 ),
                 'EXTRACT(dayofweek FROM dummy_field AT TIME ZONE "IST")',
             )
-        elif USING_DJANGO_4:
+        else:
             self.assertEqual(
                 self.db_operations.datetime_extract_sql(
                     "dayofweek", "dummy_field", None, "IST"
@@ -169,7 +169,7 @@ def test_datetime_extract_sql_use_tz_false(self):
                 ),
                 'EXTRACT(dayofweek FROM dummy_field AT TIME ZONE "UTC")',
             )
-        elif USING_DJANGO_4:
+        else:
             self.assertEqual(
                 self.db_operations.datetime_extract_sql(
                     "dayofweek", "dummy_field", None, "IST"
@@ -189,7 +189,7 @@ def test_time_extract_sql(self):
                 ),
                 'EXTRACT(dayofweek FROM dummy_field AT TIME ZONE "UTC")',
             )
-        elif USING_DJANGO_4:
+        else:
             self.assertEqual(
                 self.db_operations.time_extract_sql(
                     "dayofweek", "dummy_field"
@@ -206,7 +206,7 @@ def test_time_trunc_sql(self):
                 self.db_operations.time_trunc_sql("dayofweek", "dummy_field"),
                 'TIMESTAMP_TRUNC(dummy_field, dayofweek, "UTC")',
             )
-        elif USING_DJANGO_4:
+        else:
             self.assertEqual(
                 self.db_operations.time_trunc_sql(
                     "dayofweek", "dummy_field", None
@@ -222,7 +222,7 @@ def test_datetime_cast_date_sql(self):
                 ),
                 'DATE(dummy_field, "IST")',
             )
-        elif USING_DJANGO_4:
+        else:
             self.assertEqual(
                 self.db_operations.datetime_cast_date_sql(
                     "dummy_field", None, "IST"
@@ -239,7 +239,7 @@ def test_datetime_cast_time_sql(self):
                 ),
                 "TIMESTAMP(FORMAT_TIMESTAMP('%Y-%m-%d %R:%E9S %Z', dummy_field, 'IST'))",
             )
-        elif USING_DJANGO_4:
+        else:
             self.assertEqual(
                 self.db_operations.datetime_cast_time_sql(
                     "dummy_field", None, "IST"
@@ -259,7 +259,7 @@ def test_datetime_cast_time_sql_use_tz_false(self):
                 ),
                 "TIMESTAMP(FORMAT_TIMESTAMP('%Y-%m-%d %R:%E9S %Z', dummy_field, 'UTC'))",
             )
-        elif USING_DJANGO_4:
+        else:
             self.assertEqual(
                 self.db_operations.datetime_cast_time_sql(
                     "dummy_field", None, "IST"