chore: import upstream snapshot with attribution

contributing/samples/legacy_workflows/non_llm_sequential/agent.py

@@ -0,0 +1,35 @@
+# Copyright 2026 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.
+
+
+from google.adk.agents.llm_agent import Agent
+from google.adk.agents.sequential_agent import SequentialAgent
+
+sub_agent_1 = Agent(
+    name='sub_agent_1',
+    description='No.1 sub agent.',
+    instruction='JUST SAY 1.',
+)
+
+sub_agent_2 = Agent(
+    name='sub_agent_2',
+    description='No.2 sub agent.',
+    instruction='JUST SAY 2.',
+)
+sequential_agent = SequentialAgent(
+    name='sequential_agent',
+    sub_agents=[sub_agent_1, sub_agent_2],
+)
+
+root_agent = sequential_agent