diff --git a/google/cloud/appengine_logging_v1/types/request_log.py b/google/cloud/appengine_logging_v1/types/request_log.py
index 697299a..b54826c 100644
--- a/google/cloud/appengine_logging_v1/types/request_log.py
+++ b/google/cloud/appengine_logging_v1/types/request_log.py
@@ -28,6 +28,7 @@
 
 class LogLine(proto.Message):
     r"""Application log line emitted while processing a request.
+
     Attributes:
         time (google.protobuf.timestamp_pb2.Timestamp):
             Approximate time when this log entry was
@@ -49,6 +50,7 @@ class LogLine(proto.Message):
 
 class SourceLocation(proto.Message):
     r"""Specifies a location in a source code file.
+
     Attributes:
         file (str):
             Source file name. Depending on the runtime
diff --git a/testing/constraints-3.6.txt b/testing/constraints-3.6.txt
index 23cdd2b..a0937fc 100644
--- a/testing/constraints-3.6.txt
+++ b/testing/constraints-3.6.txt
@@ -6,6 +6,6 @@
 # e.g., if setup.py has "foo >= 1.14.0, < 2.0.0dev",
 # Then this file should have foo==1.14.0
 google-api-core==1.22.2
-proto-plus==1.10.0
+proto-plus==1.15.0
 packaging==14.3
 google-auth==1.24.0  # TODO: remove when google-auth>=1.25.0 is required through google-api-core