fix: replace unsafe six.PY3 with PY2 for better future compatibility …

…with Python 4 (#10081)

* fix: fix for Python 4: replace unsafe six.PY3 with PY2

* Fix wording

logging/tests/unit/handlers/test__helpers.py

@@ -77,7 +77,7 @@ def get(self):
         self.response.out.write(json.dumps(trace_id))
 
 
-@unittest.skipIf(six.PY3, "webapp2 is Python 2 only")
+@unittest.skipIf(not six.PY2, "webapp2 is Python 2 only")
 class Test_get_trace_id_from_webapp2(unittest.TestCase):
     @staticmethod
     def create_app():

pubsub/synth.py

@@ -127,10 +127,10 @@
     "google/cloud/pubsub_v1/gapic/publisher_client.py",
     "class PublisherClient",
     """# TODO: remove conditional import after Python 2 support is dropped
-if six.PY3:
-    from collections.abc import Mapping
-else:
+if six.PY2:
     from collections import Mapping
+else:
+    from collections.abc import Mapping
     
 
 def _merge_dict(d1, d2):

storage/google/cloud/storage/batch.py

@@ -214,10 +214,10 @@ def _prepare_batch_request(self):
             timeout = _timeout
 
         # The `email` package expects to deal with "native" strings
-        if six.PY3:  # pragma: NO COVER  Python3
-            buf = io.StringIO()
-        else:
+        if six.PY2:  # pragma: NO COVER  Python3
             buf = io.BytesIO()
+        else:
+            buf = io.StringIO()
         generator = Generator(buf, False, 0)
         generator.flatten(multi)
         payload = buf.getvalue()

storage/tests/unit/test__signing.py

@@ -69,8 +69,8 @@ def test_w_expiration_int(self):
         self.assertEqual(self._call_fut(123), 123)
 
     def test_w_expiration_long(self):
-        if six.PY3:
-            raise unittest.SkipTest("No long on Python 3")
+        if not six.PY2:
+            raise unittest.SkipTest("No long on Python 3+")
 
         self.assertEqual(self._call_fut(long(123)), 123)  # noqa: F821