[Models] Improve iteration over layers (#19497)

Signed-off-by: Lukas Geiger <lukas.geiger94@gmail.com>

vllm/model_executor/models/exaone.py

@@ -26,6 +26,7 @@
 """Inference-only Exaone model compatible with HuggingFace weights."""
 
 from collections.abc import Iterable
+from itertools import islice
 from typing import Any, Optional, Union
 
 import torch
@@ -371,7 +372,7 @@ class ExaoneModel(nn.Module):
             hidden_states = intermediate_tensors["hidden_states"]
             residual = intermediate_tensors["residual"]
 
-        for layer in self.h[self.start_layer:self.end_layer]:
+        for layer in islice(self.h, self.start_layer, self.end_layer):
             hidden_states, residual = layer(
                 positions,
                 hidden_states,