diff --git a/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/services/dashboards_service/async_client.py b/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/services/dashboards_service/async_client.py
index f3740b68be95..8f5ef278f488 100644
--- a/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/services/dashboards_service/async_client.py
+++ b/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/services/dashboards_service/async_client.py
@@ -19,14 +19,17 @@
 from typing import Dict, Sequence, Tuple, Type, Union
 import pkg_resources
 
-from google.api_core.client_options import ClientOptions  # type: ignore
-from google.api_core import exceptions as core_exceptions  # type: ignore
-from google.api_core import gapic_v1  # type: ignore
-from google.api_core import retry as retries  # type: ignore
+from google.api_core.client_options import ClientOptions
+from google.api_core import exceptions as core_exceptions
+from google.api_core import gapic_v1
+from google.api_core import retry as retries
 from google.auth import credentials as ga_credentials  # type: ignore
 from google.oauth2 import service_account  # type: ignore
 
-OptionalRetry = Union[retries.Retry, object]
+try:
+    OptionalRetry = Union[retries.Retry, gapic_v1.method._MethodDefault]
+except AttributeError:  # pragma: NO COVER
+    OptionalRetry = Union[retries.Retry, object]  # type: ignore
 
 from google.cloud.monitoring_dashboard_v1.services.dashboards_service import pagers
 from google.cloud.monitoring_dashboard_v1.types import dashboard
diff --git a/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/services/dashboards_service/client.py b/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/services/dashboards_service/client.py
index e62e3aab3109..73e36f7ef67a 100644
--- a/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/services/dashboards_service/client.py
+++ b/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/services/dashboards_service/client.py
@@ -14,23 +14,25 @@
 # limitations under the License.
 #
 from collections import OrderedDict
-from distutils import util
 import os
 import re
 from typing import Dict, Optional, Sequence, Tuple, Type, Union
 import pkg_resources
 
-from google.api_core import client_options as client_options_lib  # type: ignore
-from google.api_core import exceptions as core_exceptions  # type: ignore
-from google.api_core import gapic_v1  # type: ignore
-from google.api_core import retry as retries  # type: ignore
+from google.api_core import client_options as client_options_lib
+from google.api_core import exceptions as core_exceptions
+from google.api_core import gapic_v1
+from google.api_core import retry as retries
 from google.auth import credentials as ga_credentials  # type: ignore
 from google.auth.transport import mtls  # type: ignore
 from google.auth.transport.grpc import SslCredentials  # type: ignore
 from google.auth.exceptions import MutualTLSChannelError  # type: ignore
 from google.oauth2 import service_account  # type: ignore
 
-OptionalRetry = Union[retries.Retry, object]
+try:
+    OptionalRetry = Union[retries.Retry, gapic_v1.method._MethodDefault]
+except AttributeError:  # pragma: NO COVER
+    OptionalRetry = Union[retries.Retry, object]  # type: ignore
 
 from google.cloud.monitoring_dashboard_v1.services.dashboards_service import pagers
 from google.cloud.monitoring_dashboard_v1.types import dashboard
@@ -301,8 +303,15 @@ def __init__(
             client_options = client_options_lib.ClientOptions()
 
         # Create SSL credentials for mutual TLS if needed.
-        use_client_cert = bool(
-            util.strtobool(os.getenv("GOOGLE_API_USE_CLIENT_CERTIFICATE", "false"))
+        if os.getenv("GOOGLE_API_USE_CLIENT_CERTIFICATE", "false") not in (
+            "true",
+            "false",
+        ):
+            raise ValueError(
+                "Environment variable `GOOGLE_API_USE_CLIENT_CERTIFICATE` must be either `true` or `false`"
+            )
+        use_client_cert = (
+            os.getenv("GOOGLE_API_USE_CLIENT_CERTIFICATE", "false") == "true"
         )
 
         client_cert_source_func = None
diff --git a/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/services/dashboards_service/transports/base.py b/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/services/dashboards_service/transports/base.py
index 15c892c4444a..53678cc7566f 100644
--- a/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/services/dashboards_service/transports/base.py
+++ b/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/services/dashboards_service/transports/base.py
@@ -18,10 +18,10 @@
 import pkg_resources
 
 import google.auth  # type: ignore
-import google.api_core  # type: ignore
-from google.api_core import exceptions as core_exceptions  # type: ignore
-from google.api_core import gapic_v1  # type: ignore
-from google.api_core import retry as retries  # type: ignore
+import google.api_core
+from google.api_core import exceptions as core_exceptions
+from google.api_core import gapic_v1
+from google.api_core import retry as retries
 from google.auth import credentials as ga_credentials  # type: ignore
 from google.oauth2 import service_account  # type: ignore
 
diff --git a/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/services/dashboards_service/transports/grpc.py b/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/services/dashboards_service/transports/grpc.py
index 39fdb5197b15..6fe927a43f50 100644
--- a/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/services/dashboards_service/transports/grpc.py
+++ b/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/services/dashboards_service/transports/grpc.py
@@ -16,8 +16,8 @@
 import warnings
 from typing import Callable, Dict, Optional, Sequence, Tuple, Union
 
-from google.api_core import grpc_helpers  # type: ignore
-from google.api_core import gapic_v1  # type: ignore
+from google.api_core import grpc_helpers
+from google.api_core import gapic_v1
 import google.auth  # type: ignore
 from google.auth import credentials as ga_credentials  # type: ignore
 from google.auth.transport.grpc import SslCredentials  # type: ignore
diff --git a/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/services/dashboards_service/transports/grpc_asyncio.py b/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/services/dashboards_service/transports/grpc_asyncio.py
index fc8a54b7546e..c5a03514e96f 100644
--- a/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/services/dashboards_service/transports/grpc_asyncio.py
+++ b/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/services/dashboards_service/transports/grpc_asyncio.py
@@ -16,8 +16,8 @@
 import warnings
 from typing import Awaitable, Callable, Dict, Optional, Sequence, Tuple, Union
 
-from google.api_core import gapic_v1  # type: ignore
-from google.api_core import grpc_helpers_async  # type: ignore
+from google.api_core import gapic_v1
+from google.api_core import grpc_helpers_async
 from google.auth import credentials as ga_credentials  # type: ignore
 from google.auth.transport.grpc import SslCredentials  # type: ignore
 
diff --git a/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/types/dashboard.py b/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/types/dashboard.py
index 42b6b484e45f..9ef8a54d2cd7 100644
--- a/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/types/dashboard.py
+++ b/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/types/dashboard.py
@@ -53,19 +53,23 @@ class Dashboard(proto.Message):
             Content is arranged with a basic layout that
             re-flows a simple list of informational elements
             like widgets or tiles.
+
             This field is a member of `oneof`_ ``layout``.
         mosaic_layout (google.cloud.monitoring_dashboard_v1.types.MosaicLayout):
             The content is arranged as a grid of tiles,
             with each content widget occupying one or more
             grid blocks.
+
             This field is a member of `oneof`_ ``layout``.
         row_layout (google.cloud.monitoring_dashboard_v1.types.RowLayout):
             The content is divided into equally spaced
             rows and the widgets are arranged horizontally.
+
             This field is a member of `oneof`_ ``layout``.
         column_layout (google.cloud.monitoring_dashboard_v1.types.ColumnLayout):
             The content is divided into equally spaced
             columns and the widgets are arranged vertically.
+
             This field is a member of `oneof`_ ``layout``.
     """
 
diff --git a/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/types/metrics.py b/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/types/metrics.py
index 164e973d41dd..db864ff6802a 100644
--- a/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/types/metrics.py
+++ b/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/types/metrics.py
@@ -53,13 +53,16 @@ class TimeSeriesQuery(proto.Message):
     Attributes:
         time_series_filter (google.cloud.monitoring_dashboard_v1.types.TimeSeriesFilter):
             Filter parameters to fetch time series.
+
             This field is a member of `oneof`_ ``source``.
         time_series_filter_ratio (google.cloud.monitoring_dashboard_v1.types.TimeSeriesFilterRatio):
             Parameters to fetch a ratio between two time
             series filters.
+
             This field is a member of `oneof`_ ``source``.
         time_series_query_language (str):
             A query used to fetch time series.
+
             This field is a member of `oneof`_ ``source``.
         unit_override (str):
             The unit of data contained in fetched time series. If
@@ -106,11 +109,13 @@ class TimeSeriesFilter(proto.Message):
             Apply a second aggregation after ``aggregation`` is applied.
         pick_time_series_filter (google.cloud.monitoring_dashboard_v1.types.PickTimeSeriesFilter):
             Ranking based time series filter.
+
             This field is a member of `oneof`_ ``output_filter``.
         statistical_time_series_filter (google.cloud.monitoring_dashboard_v1.types.StatisticalTimeSeriesFilter):
             Statistics based time series filter.
             Note: This field is deprecated and completely
             ignored by the API.
+
             This field is a member of `oneof`_ ``output_filter``.
     """
 
@@ -156,11 +161,13 @@ class TimeSeriesFilterRatio(proto.Message):
             computed.
         pick_time_series_filter (google.cloud.monitoring_dashboard_v1.types.PickTimeSeriesFilter):
             Ranking based time series filter.
+
             This field is a member of `oneof`_ ``output_filter``.
         statistical_time_series_filter (google.cloud.monitoring_dashboard_v1.types.StatisticalTimeSeriesFilter):
             Statistics based time series filter.
             Note: This field is deprecated and completely
             ignored by the API.
+
             This field is a member of `oneof`_ ``output_filter``.
     """
 
diff --git a/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/types/scorecard.py b/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/types/scorecard.py
index 2ecb55229450..c0b06ba97bf9 100644
--- a/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/types/scorecard.py
+++ b/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/types/scorecard.py
@@ -42,10 +42,12 @@ class Scorecard(proto.Message):
         gauge_view (google.cloud.monitoring_dashboard_v1.types.Scorecard.GaugeView):
             Will cause the scorecard to show a gauge
             chart.
+
             This field is a member of `oneof`_ ``data_view``.
         spark_chart_view (google.cloud.monitoring_dashboard_v1.types.Scorecard.SparkChartView):
             Will cause the scorecard to show a spark
             chart.
+
             This field is a member of `oneof`_ ``data_view``.
         thresholds (Sequence[google.cloud.monitoring_dashboard_v1.types.Threshold]):
             The thresholds used to determine the state of
diff --git a/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/types/widget.py b/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/types/widget.py
index d870a6707b5b..b640881203cd 100644
--- a/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/types/widget.py
+++ b/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/types/widget.py
@@ -43,19 +43,24 @@ class Widget(proto.Message):
             Optional. The title of the widget.
         xy_chart (google.cloud.monitoring_dashboard_v1.types.XyChart):
             A chart of time series data.
+
             This field is a member of `oneof`_ ``content``.
         scorecard (google.cloud.monitoring_dashboard_v1.types.Scorecard):
             A scorecard summarizing time series data.
+
             This field is a member of `oneof`_ ``content``.
         text (google.cloud.monitoring_dashboard_v1.types.Text):
             A raw string or markdown displaying textual
             content.
+
             This field is a member of `oneof`_ ``content``.
         blank (google.protobuf.empty_pb2.Empty):
             A blank space.
+
             This field is a member of `oneof`_ ``content``.
         alert_chart (google.cloud.monitoring_dashboard_v1.types.AlertChart):
             A chart of alert policy data.
+
             This field is a member of `oneof`_ ``content``.
     """