Add custom OpenAIModel implementation

app.py

@@ -1,5 +1,5 @@
 from smolagents import CodeAgent, DuckDuckGoSearchTool, load_tool, tool
-from smolagents.models import OpenAIModel
+from models import OpenAIModel  # Import our local model
 import datetime
 import requests
 import pytz

models.py

@@ -0,0 +1,17 @@
+from openai import OpenAI
+
+class OpenAIModel:
+    def __init__(self, model="gpt-4-turbo-preview", max_tokens=4096, temperature=0.7, api_key=None):
+        self.model = model
+        self.max_tokens = max_tokens
+        self.temperature = temperature
+        self.client = OpenAI(api_key=api_key)
+    
+    def generate(self, messages):
+        response = self.client.chat.completions.create(
+            model=self.model,
+            messages=messages,
+            max_tokens=self.max_tokens,
+            temperature=self.temperature
+        )
+        return response.choices[0].message.content