fixiing required engines definition

exo/api/chatgpt_api.py

@@ -222,14 +222,13 @@ class ChatGPTAPI:
         if model_name in model_cards:
           model_info = model_cards[model_name]
           
-          # Get required engines
-          required_engines = list(dict.fromkeys([
-              inference_engine_classes.get(engine_name, None) 
-              for engine_list in self.node.topology_inference_engines_pool 
-              for engine_name in engine_list 
-              if engine_name is not None
-          ] + [self.inference_engine_classname]))
-          
+          # Get required engines from the node's topology directly
+          required_engines = list(dict.fromkeys(
+              [engine_name for engine_list in self.node.topology_inference_engines_pool 
+               for engine_name in engine_list 
+               if engine_name is not None] + 
+              [self.inference_engine_classname]
+          ))          
           # Check if model supports required engines
           if all(map(lambda engine: engine in model_info["repo"], required_engines)):
             shard = build_base_shard(model_name, self.inference_engine_classname)