Python: ChatHistorySummarizationReducer.restore_chat_history() doesn't restore the correct service type

[danielescaramuzzi]

Describe the bug
When restoring a serialized chat history using ChatHistorySummarizationReducer.restore_chat_history(), service type is not set correctly.

To Reproduce

import asyncio

from semantic_kernel import Kernel
from semantic_kernel.contents import ChatHistorySummarizationReducer
from semantic_kernel.connectors.ai.open_ai import AzureChatCompletion

kernel = Kernel()
service_id = "my-service"
kernel.add_service(AzureChatCompletion(
            service_id=service_id,
            api_key="***",
            api_version="2024-10-21",
            endpoint="***",
            deployment_name="gpt-4o-mini"
        ))

chat_history = ChatHistorySummarizationReducer(
            service=kernel.get_service(service_id, AzureChatCompletion),
            target_count=2,
            threshold_count=1,
            include_function_content_in_summary=False,
        )

print(f"Service type: {type(chat_history.service)}")

chat_history.add_assistant_message("Hey there! How can I assist you today?")
chat_history.add_user_message("What is the weather like today?")
chat_history.add_assistant_message("The weather is sunny with a high of 25 degrees Celsius.") 
chat_history.add_user_message("How are you?")
chat_history.add_assistant_message("I'm fine thanks for asking! How can I help you further?") 

serialized_history = chat_history.serialize()
import json
json_serialized_history = json.loads(serialized_history)
print(f"Serialized service section: {json_serialized_history['service']}")

# restore from serialized history
restored_chat_history = ChatHistorySummarizationReducer.restore_chat_history(serialized_history)
print(f"Restored service type: {type(restored_chat_history.service)}")

async def main() -> None:
  reduced = await restored_chat_history.reduce()
  print(f"Reduced: {reduced}")

if __name__ == "__main__":
    asyncio.run(main())

produces the following output:

Service type: <class 'semantic_kernel.connectors.ai.open_ai.services.azure_chat_completion.AzureChatCompletion'>

Serialized service section: {'ai_model_id': 'gpt-4o-mini', 'service_id': 'my-service', 'instruction_role': 'system'}

Restored service type: <class 'semantic_kernel.connectors.ai.chat_completion_client_base.ChatCompletionClientBase'>


Summarization failed, continuing without summary.
Traceback (most recent call last):
  File "***/.venv/lib/python3.12/site-packages/semantic_kernel/contents/history_reducer/chat_history_summarization_reducer.py", line 127, in reduce
    summary_msg = await self._summarize(messages_to_summarize)
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "***/.venv/lib/python3.12/site-packages/semantic_kernel/contents/history_reducer/chat_history_summarization_reducer.py", line 166, in _summarize
    return await self.service.get_chat_message_content(chat_history=chat_history, settings=execution_settings)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "***/.venv/lib/python3.12/site-packages/semantic_kernel/connectors/ai/chat_completion_client_base.py", line 190, in get_chat_message_content
    results = await self.get_chat_message_contents(chat_history=chat_history, settings=settings, **kwargs)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "***/.venv/lib/python3.12/site-packages/semantic_kernel/connectors/ai/chat_completion_client_base.py", line 113, in get_chat_message_contents
    return await self._inner_get_chat_message_contents(chat_history, settings)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "***/.venv/lib/python3.12/site-packages/semantic_kernel/connectors/ai/chat_completion_client_base.py", line 58, in _inner_get_chat_message_contents
    raise NotImplementedError("The _inner_get_chat_message_contents method is not implemented.")
NotImplementedError: The _inner_get_chat_message_contents method is not implemented.

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "***/./bug_restore_history.py", line 46, in <module>
    asyncio.run(main())
  File "***/.pyenv/versions/3.12.3/lib/python3.12/asyncio/runners.py", line 194, in run
    return runner.run(main)
           ^^^^^^^^^^^^^^^^
  File "***/.pyenv/versions/3.12.3/lib/python3.12/asyncio/runners.py", line 118, in run
    return self._loop.run_until_complete(task)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "***/.pyenv/versions/3.12.3/lib/python3.12/asyncio/base_events.py", line 687, in run_until_complete
    return future.result()
           ^^^^^^^^^^^^^^^
  File "***/./bug_restore_history.py", line 42, in main
    reduced = await restored_chat_history.reduce()
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "***/.venv/lib/python3.12/site-packages/semantic_kernel/contents/history_reducer/chat_history_summarization_reducer.py", line 149, in reduce
    raise ChatHistoryReducerException("Chat History Summarization failed.") from ex
semantic_kernel.exceptions.content_exceptions.ChatHistoryReducerException: Chat History Summarization failed.

Expected behavior
When serializing and deserializing chat history, service type should not change.

Platform

• Language: Python
• Version: semantic-kernel==1.33.0