correct verbose setting method and improve exponential backoff calculation

app.py

@@ -9,7 +9,7 @@ import litellm
 from litellm import RateLimitError
 
 # Enable debug mode to see detailed error information
-litellm.set_verbose(True)
+litellm.verbose = True
 from smolagents import (
     CodeAgent,
     DuckDuckGoSearchTool,
@@ -142,7 +142,7 @@ class RateLimitedModel:
                         # Use exponential backoff for 503 errors, longer delays
                         if is_server_overload:
                             delay = min(
-                                120, self.base_delay * (2 ** attempt)
+                                120, self.base_delay * (2**attempt)
                             ) + random.uniform(0, 10)
                         else:
                             delay = self.base_delay + random.uniform(0, 5)