refactor: simplify gpt session

src/apis/gpt.py

@@ -7,12 +7,7 @@ import openai
 from langchain.callbacks import CallbackManager
 from langchain.chat_models import ChatOpenAI
 from openai.error import RateLimitError
-from langchain.schema import (
-    AIMessage,
-    HumanMessage,
-    SystemMessage,
-    BaseMessage
-)
+from langchain.schema import AIMessage, HumanMessage, SystemMessage, BaseMessage
 from langchain.callbacks.streaming_stdout import StreamingStdOutCallbackHandler
 
 from src.options.generate.prompt_system import system_message_base, executor_example, docarray_example, client_example
@@ -22,13 +17,7 @@ from src.utils.string_tools import print_colored
 class GPTSession:
     def __init__(self, model: str = 'gpt-4'):
         self.configure_openai_api_key()
-        if model == 'gpt-4' and self.is_gpt4_available():
-            self.supported_model = 'gpt-4'
-        else:
-            if model == 'gpt-4':
-                print_colored('GPT-4 is not available. Using GPT-3.5-turbo instead.', 'yellow')
-                model = 'gpt-3.5-turbo'
-            self.supported_model = model
+        self.model_name = 'gpt-4' if model == 'gpt-4' and self.is_gpt4_available() else 'gpt-3.5-turbo'
 
     @staticmethod
     def configure_openai_api_key():
@@ -58,10 +47,11 @@ If you have updated it already, please restart your terminal.
                     continue
             return True
         except openai.error.InvalidRequestError:
+            print_colored('GPT-4 is not available. Using GPT-3.5-turbo instead.', 'yellow')
             return False
 
     def get_conversation(self, system_definition_examples: List[str] = ['executor', 'docarray', 'client']):
-        return _GPTConversation(self.supported_model, system_definition_examples)
+        return _GPTConversation(self.model_name, system_definition_examples)
 
 
 class AssistantStreamingStdOutCallbackHandler(StreamingStdOutCallbackHandler):