code: def test_compress_message():
      assistant = CompressibleAgent(
          name="assistant",
          llm_config={
              "timeout": 600,
              "cache_seed": 43,
              "config_list": config_list,
              "model": "gpt-3.5-turbo",
          },
          compress_config={
              "mode": "COMPRESS",
              "trigger_count": 600,
              "verbose": True,
              "leave_last_n": 0,
          },
      )
  
      assert assistant.compress_messages(
          [{"content": "hello world", "role": "user"}]
      ) == (
          False,
          None,
      ), "Single message should not be compressed"
  
      is_success, _ = assistant.compress_messages(
          [
              {"content": "Hello!", "role": "user"},
              {
                  "content": "How can I help you today?",
                  "role": "assistant",
              },
              {
                  "content": "Can you tell me a joke about programming?",
                  "role": "assistant",
              },
          ]
      )
      assert is_success, "Compression failed."
  
file_path: autogen/test/agentchat/contrib/test_compressible_agent.py
imports: import pytest
  import sys
  import autogen
  import os
  from autogen.agentchat.contrib.compressible_agent import CompressibleAgent
  from conftest import skip_openai
  from test_assistant_agent import OAI_CONFIG_LIST, KEY_LOC
label_desc: Use image node_id 3 for calling a global function with example usage: test_compress_message() without return types