Add deprecation notice to 'gs' backend
+# DEPRECATION NOTICE: This backend is deprecated in favour of the
+# "gcloud" backend. This backend uses Google Cloud Storage's XML
+# Interoperable API which uses keyed-hash message authentication code
+# (a.k.a. developer keys) that are linked to your Google account. The
+# interoperable API is really meant for migration to Google Cloud
+# Storage. The biggest problem with the developer keys is security and
+# privacy. Developer keys should not be shared with anyone as they can
+# be used to gain access to other Google Cloud Storage buckets linked
+# to your Google account.
+
from django.core.exceptions import ImproperlyConfigured
from django.utils.deconstruct import deconstructible
from django.utils.six import BytesIO
