feat: add support for 'Blob.custom_time' and lifecycle rules

google/cloud/storage/blob.py

@@ -3196,11 +3196,14 @@ def custom_time(self, value):
 
         See https://cloud.google.com/storage/docs/json_api/v1/objects
 
-        :type value: :class:`datetime.datetime`
+        :type value: :class:`datetime.datetime` or ``NoneType``
         :param value: (Optional) Set the custom time of blob. Datetime object parsed
                                  from RFC3339 valid timestamp.
         """
-        self._properties["customTime"] = _datetime_to_rfc3339(value)
+        if value is not None:
+            value = _datetime_to_rfc3339(value)
+
+        self._properties["customTime"] = value
 
 
 def _get_encryption_headers(key, source=False):

tests/unit/test_blob.py

@@ -4152,6 +4152,14 @@ def test_custom_time_setter(self):
         blob.custom_time = TIMESTAMP
         self.assertEqual(blob.custom_time, TIMESTAMP)
 
+    def test_custom_time_setter_none_value(self):
+        BLOB_NAME = "blob-name"
+        bucket = _Bucket()
+        TIMESTAMP = None
+        blob = self._make_one(BLOB_NAME, bucket=bucket)
+        blob.custom_time = TIMESTAMP
+        self.assertIsNone(blob.custom_time)
+
     def test_custom_time_unset(self):
         BUCKET = object()
         blob = self._make_one("blob-name", bucket=BUCKET)