code: def test_run_prompt_without_skills(self, agent):
      agent.chat("How many countries are in the dataframe?")
  
      last_prompt = agent._lake.last_prompt
  
      assert "<function>" not in last_prompt
      assert "</function>" not in last_prompt
      assert (
          "You can call the following functions that have been pre-defined for you:"
          not in last_prompt
      )
  
imports: from typing import Optional
  from unittest.mock import MagicMock, Mock, patch
  import uuid
  import pandas
  import pytest
  from pandasai.agent import Agent
  from pandasai.helpers.code_manager import CodeExecutionContext, CodeManager
  from pandasai.helpers.skills_manager import SkillsManager
  from pandasai.llm.fake import FakeLLM
  from pandasai.skills import skill, Skill
  from pandasai.smart_dataframe import SmartDataframe
label_desc: Use image node_id 17 for calling the TestSkills obj's underlying member method code with example usage: obj.test_run_prompt_without_skills(agent) without return types