diff --git a/.librarian/generator-input/client-post-processing/remove-unused-imports.yaml b/.librarian/generator-input/client-post-processing/remove-unused-imports.yaml
deleted file mode 100644
index 3ddb3835e8bb..000000000000
--- a/.librarian/generator-input/client-post-processing/remove-unused-imports.yaml
+++ /dev/null
@@ -1,33 +0,0 @@
-# Copyright 2023 Google LLC
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#      http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-description: Remove unused imports
-url: https://github.com/googleapis/gapic-generator-python/issues/1833
-replacements:
-  - paths: [
-      packages/google-cloud-gke-hub/tests/unit/gapic/gkehub_v1/test_gke_hub.py
-    ]
-    before: |
-      import google.cloud.gkehub.configmanagement.v1.configmanagement_pb2 as configmanagement_pb2  # type: ignore
-      import google.cloud.gkehub.multiclusteringress.v1.multiclusteringress_pb2 as multiclusteringress_pb2  # type: ignore
-      import google.cloud.gkehub.rbacrolebindingactuation.v1.rbacrolebindingactuation_pb2 as rbacrolebindingactuation_pb2  # type: ignore
-    after:  ""
-    count: 1
-  - paths: [
-      packages/google-cloud-binary-authorization/tests/unit/gapic/binaryauthorization_v1/test_validation_helper_v1.py
-    ]
-    before: |
-      import grafeas.v1.attestation_pb2 as attestation_pb2  # type: ignore
-      import grafeas.v1.common_pb2 as common_pb2  # type: ignore
-    after:  ""
-    count: 1
diff --git a/packages/gapic-generator/gapic/ads-templates/tests/unit/gapic/%name_%version/%sub/test_%service.py.j2 b/packages/gapic-generator/gapic/ads-templates/tests/unit/gapic/%name_%version/%sub/test_%service.py.j2
index 23c905cce276..6c051147f937 100644
--- a/packages/gapic-generator/gapic/ads-templates/tests/unit/gapic/%name_%version/%sub/test_%service.py.j2
+++ b/packages/gapic-generator/gapic/ads-templates/tests/unit/gapic/%name_%version/%sub/test_%service.py.j2
@@ -57,7 +57,7 @@ from google.longrunning import operations_pb2 # type: ignore
 {% endif %}
 from google.api_core import gapic_v1
 {% for method in service.methods.values() %}
-{% for ref_type in method.ref_types
+{% for ref_type in method.flat_ref_types
    if not ((ref_type.ident.python_import.package == ('google', 'api_core') and ref_type.ident.python_import.module == 'operation')
            or ref_type.ident.python_import.package == ('google', 'protobuf') and ref_type.ident.python_import.module == 'empty_pb2') %}
 {{ ref_type.ident.python_import }}
diff --git a/packages/gapic-generator/gapic/templates/tests/unit/gapic/%name_%version/%sub/test_%service.py.j2 b/packages/gapic-generator/gapic/templates/tests/unit/gapic/%name_%version/%sub/test_%service.py.j2
index f445db3a721b..c72fb3f5dc34 100644
--- a/packages/gapic-generator/gapic/templates/tests/unit/gapic/%name_%version/%sub/test_%service.py.j2
+++ b/packages/gapic-generator/gapic/templates/tests/unit/gapic/%name_%version/%sub/test_%service.py.j2
@@ -86,7 +86,7 @@ from google.longrunning import operations_pb2 # type: ignore
 {% endif %}
 from google.api_core import gapic_v1
 {% for method in service.methods.values() %}
-{% for ref_type in method.ref_types
+{% for ref_type in method.flat_ref_types
    if not (ref_type.ident.python_import.package == ('google', 'api_core') and ref_type.ident.python_import.module == 'operation') %}
 {{ ref_type.ident.python_import }}
 {% endfor %}
diff --git a/packages/gapic-generator/tests/integration/goldens/asset/tests/unit/gapic/asset_v1/test_asset_service.py b/packages/gapic-generator/tests/integration/goldens/asset/tests/unit/gapic/asset_v1/test_asset_service.py
index 624dae1d6279..2df35ac7af42 100755
--- a/packages/gapic-generator/tests/integration/goldens/asset/tests/unit/gapic/asset_v1/test_asset_service.py
+++ b/packages/gapic-generator/tests/integration/goldens/asset/tests/unit/gapic/asset_v1/test_asset_service.py
@@ -62,7 +62,6 @@
 from google.oauth2 import service_account
 import google.api_core.operation_async as operation_async  # type: ignore
 import google.auth
-import google.protobuf.duration_pb2 as duration_pb2  # type: ignore
 import google.protobuf.field_mask_pb2 as field_mask_pb2  # type: ignore
 import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
 import google.rpc.status_pb2 as status_pb2  # type: ignore
diff --git a/packages/gapic-generator/tests/integration/goldens/eventarc/tests/unit/gapic/eventarc_v1/test_eventarc.py b/packages/gapic-generator/tests/integration/goldens/eventarc/tests/unit/gapic/eventarc_v1/test_eventarc.py
index 31e992ed4261..a1c06b19b6f7 100755
--- a/packages/gapic-generator/tests/integration/goldens/eventarc/tests/unit/gapic/eventarc_v1/test_eventarc.py
+++ b/packages/gapic-generator/tests/integration/goldens/eventarc/tests/unit/gapic/eventarc_v1/test_eventarc.py
@@ -71,7 +71,6 @@
 from google.cloud.eventarc_v1.types import logging_config
 from google.cloud.eventarc_v1.types import message_bus
 from google.cloud.eventarc_v1.types import message_bus as gce_message_bus
-from google.cloud.eventarc_v1.types import network_config
 from google.cloud.eventarc_v1.types import pipeline
 from google.cloud.eventarc_v1.types import pipeline as gce_pipeline
 from google.cloud.eventarc_v1.types import trigger
@@ -84,10 +83,8 @@
 from google.oauth2 import service_account
 import google.api_core.operation_async as operation_async  # type: ignore
 import google.auth
-import google.protobuf.duration_pb2 as duration_pb2  # type: ignore
 import google.protobuf.field_mask_pb2 as field_mask_pb2  # type: ignore
 import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
-import google.rpc.code_pb2 as code_pb2  # type: ignore
 
 
 
diff --git a/packages/gapic-generator/tests/integration/goldens/logging/tests/unit/gapic/logging_v2/test_logging_service_v2.py b/packages/gapic-generator/tests/integration/goldens/logging/tests/unit/gapic/logging_v2/test_logging_service_v2.py
index 981fe7c5c569..b961e45ea907 100755
--- a/packages/gapic-generator/tests/integration/goldens/logging/tests/unit/gapic/logging_v2/test_logging_service_v2.py
+++ b/packages/gapic-generator/tests/integration/goldens/logging/tests/unit/gapic/logging_v2/test_logging_service_v2.py
@@ -53,12 +53,6 @@
 from google.oauth2 import service_account
 import google.api.monitored_resource_pb2 as monitored_resource_pb2  # type: ignore
 import google.auth
-import google.logging.type.http_request_pb2 as http_request_pb2  # type: ignore
-import google.logging.type.log_severity_pb2 as log_severity_pb2  # type: ignore
-import google.protobuf.any_pb2 as any_pb2  # type: ignore
-import google.protobuf.duration_pb2 as duration_pb2  # type: ignore
-import google.protobuf.struct_pb2 as struct_pb2  # type: ignore
-import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
 
 
 
diff --git a/packages/gapic-generator/tests/integration/goldens/logging/tests/unit/gapic/logging_v2/test_metrics_service_v2.py b/packages/gapic-generator/tests/integration/goldens/logging/tests/unit/gapic/logging_v2/test_metrics_service_v2.py
index b75b76971760..ef11eed3796f 100755
--- a/packages/gapic-generator/tests/integration/goldens/logging/tests/unit/gapic/logging_v2/test_metrics_service_v2.py
+++ b/packages/gapic-generator/tests/integration/goldens/logging/tests/unit/gapic/logging_v2/test_metrics_service_v2.py
@@ -51,11 +51,8 @@
 from google.longrunning import operations_pb2 # type: ignore
 from google.oauth2 import service_account
 import google.api.distribution_pb2 as distribution_pb2  # type: ignore
-import google.api.label_pb2 as label_pb2  # type: ignore
-import google.api.launch_stage_pb2 as launch_stage_pb2  # type: ignore
 import google.api.metric_pb2 as metric_pb2  # type: ignore
 import google.auth
-import google.protobuf.duration_pb2 as duration_pb2  # type: ignore
 import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
 
 
diff --git a/packages/gapic-generator/tests/integration/goldens/logging_internal/tests/unit/gapic/logging_v2/test_logging_service_v2.py b/packages/gapic-generator/tests/integration/goldens/logging_internal/tests/unit/gapic/logging_v2/test_logging_service_v2.py
index 981fe7c5c569..b961e45ea907 100755
--- a/packages/gapic-generator/tests/integration/goldens/logging_internal/tests/unit/gapic/logging_v2/test_logging_service_v2.py
+++ b/packages/gapic-generator/tests/integration/goldens/logging_internal/tests/unit/gapic/logging_v2/test_logging_service_v2.py
@@ -53,12 +53,6 @@
 from google.oauth2 import service_account
 import google.api.monitored_resource_pb2 as monitored_resource_pb2  # type: ignore
 import google.auth
-import google.logging.type.http_request_pb2 as http_request_pb2  # type: ignore
-import google.logging.type.log_severity_pb2 as log_severity_pb2  # type: ignore
-import google.protobuf.any_pb2 as any_pb2  # type: ignore
-import google.protobuf.duration_pb2 as duration_pb2  # type: ignore
-import google.protobuf.struct_pb2 as struct_pb2  # type: ignore
-import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
 
 
 
diff --git a/packages/gapic-generator/tests/integration/goldens/logging_internal/tests/unit/gapic/logging_v2/test_metrics_service_v2.py b/packages/gapic-generator/tests/integration/goldens/logging_internal/tests/unit/gapic/logging_v2/test_metrics_service_v2.py
index 3cbb28eec983..df7160640471 100755
--- a/packages/gapic-generator/tests/integration/goldens/logging_internal/tests/unit/gapic/logging_v2/test_metrics_service_v2.py
+++ b/packages/gapic-generator/tests/integration/goldens/logging_internal/tests/unit/gapic/logging_v2/test_metrics_service_v2.py
@@ -51,11 +51,8 @@
 from google.longrunning import operations_pb2 # type: ignore
 from google.oauth2 import service_account
 import google.api.distribution_pb2 as distribution_pb2  # type: ignore
-import google.api.label_pb2 as label_pb2  # type: ignore
-import google.api.launch_stage_pb2 as launch_stage_pb2  # type: ignore
 import google.api.metric_pb2 as metric_pb2  # type: ignore
 import google.auth
-import google.protobuf.duration_pb2 as duration_pb2  # type: ignore
 import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
 
 
diff --git a/packages/gapic-generator/tests/integration/goldens/redis/tests/unit/gapic/redis_v1/test_cloud_redis.py b/packages/gapic-generator/tests/integration/goldens/redis/tests/unit/gapic/redis_v1/test_cloud_redis.py
index f9f5e27adf58..0de09163e097 100755
--- a/packages/gapic-generator/tests/integration/goldens/redis/tests/unit/gapic/redis_v1/test_cloud_redis.py
+++ b/packages/gapic-generator/tests/integration/goldens/redis/tests/unit/gapic/redis_v1/test_cloud_redis.py
@@ -69,12 +69,9 @@
 from google.oauth2 import service_account
 import google.api_core.operation_async as operation_async  # type: ignore
 import google.auth
-import google.protobuf.duration_pb2 as duration_pb2  # type: ignore
 import google.protobuf.empty_pb2 as empty_pb2  # type: ignore
 import google.protobuf.field_mask_pb2 as field_mask_pb2  # type: ignore
 import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
-import google.type.dayofweek_pb2 as dayofweek_pb2  # type: ignore
-import google.type.timeofday_pb2 as timeofday_pb2  # type: ignore
 
 
 
diff --git a/packages/gapic-generator/tests/integration/goldens/redis_selective/tests/unit/gapic/redis_v1/test_cloud_redis.py b/packages/gapic-generator/tests/integration/goldens/redis_selective/tests/unit/gapic/redis_v1/test_cloud_redis.py
index 2328c8c618c1..a7f6c15a439c 100755
--- a/packages/gapic-generator/tests/integration/goldens/redis_selective/tests/unit/gapic/redis_v1/test_cloud_redis.py
+++ b/packages/gapic-generator/tests/integration/goldens/redis_selective/tests/unit/gapic/redis_v1/test_cloud_redis.py
@@ -69,12 +69,9 @@
 from google.oauth2 import service_account
 import google.api_core.operation_async as operation_async  # type: ignore
 import google.auth
-import google.protobuf.duration_pb2 as duration_pb2  # type: ignore
 import google.protobuf.empty_pb2 as empty_pb2  # type: ignore
 import google.protobuf.field_mask_pb2 as field_mask_pb2  # type: ignore
 import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
-import google.type.dayofweek_pb2 as dayofweek_pb2  # type: ignore
-import google.type.timeofday_pb2 as timeofday_pb2  # type: ignore
 
 
 
diff --git a/packages/gapic-generator/tests/integration/goldens/storagebatchoperations/tests/unit/gapic/storagebatchoperations_v1/test_storage_batch_operations.py b/packages/gapic-generator/tests/integration/goldens/storagebatchoperations/tests/unit/gapic/storagebatchoperations_v1/test_storage_batch_operations.py
index 2db6f81e5e3f..8dd4ede89d60 100755
--- a/packages/gapic-generator/tests/integration/goldens/storagebatchoperations/tests/unit/gapic/storagebatchoperations_v1/test_storage_batch_operations.py
+++ b/packages/gapic-generator/tests/integration/goldens/storagebatchoperations/tests/unit/gapic/storagebatchoperations_v1/test_storage_batch_operations.py
@@ -65,7 +65,6 @@
 import google.api_core.operation_async as operation_async  # type: ignore
 import google.auth
 import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
-import google.rpc.code_pb2 as code_pb2  # type: ignore