text: Title: TypeError for path
  Body: **Describe the bug**
  I am using DemoGPT on MAC, and ran into TypeError once I submitted.
  
  **To Reproduce**
  Steps to reproduce the behavior:
  1. On terminal, run app with command `streamlit run app.py`
  2. Click on the example Language Translator
  3. Click submit button
  4. See error
  
  **Error Message**
  `
  Language Translator 📝
  2023-07-03 17:26:34.783 Uncaught app exception
  Traceback (most recent call last):
    File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/streamlit/runtime/scriptrunner/script_runner.py", line 552, in _run_script
      exec(code, module.__dict__)
    File "/Users/mchuang/Desktop/Testing tools/DemoGPT/src/prompt_based/app.py", line 67, in <module>
      for data in generate_response(demo_idea):
    File "/Users/mchuang/Desktop/Testing tools/DemoGPT/src/prompt_based/app.py", line 16, in generate_response
      for data in agent(txt,num_of_iterations):
    File "/Users/mchuang/Desktop/Testing tools/DemoGPT/src/prompt_based/model.py", line 69, in __call__
      response, error = self.run_python(total_code)
    File "/Users/mchuang/Desktop/Testing tools/DemoGPT/src/prompt_based/model.py", line 35, in run_python
      process = subprocess.Popen([python_path,tmp.name], env=environmental_variables,stdout=PIPE, stderr=PIPE)
    File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/subprocess.py", line 966, in __init__
      self._execute_child(args, executable, preexec_fn, close_fds,
    File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/subprocess.py", line 1717, in _execute_child
      and os.path.dirname(executable)
    File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/posixpath.py", line 152, in dirname
      p = os.fspath(p)
  TypeError: expected str, bytes or os.PathLike object, not NoneType
  `
  
  **Screenshots**
  <img width="751" alt="image" src="https://github.com/melih-unsal/DemoGPT/assets/25274391/1fd0cbd5-a9ba-4e0f-a576-eb9806724799">
  
  **Desktop (please complete the following information):**
   - OS: macOS Monterey ver.12.3.1
   - Browser: Chrome
   - Version: 114.0.5735.106
  