diff --git a/examples/arm/aot_arm_compiler.py b/examples/arm/aot_arm_compiler.py
index b0597ed1cf..04bdb3f3cf 100644
--- a/examples/arm/aot_arm_compiler.py
+++ b/examples/arm/aot_arm_compiler.py
@@ -153,6 +153,37 @@ def forward(self, x):
     "TOSA",
 ]
 
+
+def get_compile_spec(target: str) -> ArmCompileSpecBuilder:
+    if target == "TOSA":
+        return (
+            ArmCompileSpecBuilder().tosa_compile_spec().set_permute_memory_format(True)
+        )
+    elif target == "ethos-u55-128":
+        return (
+            ArmCompileSpecBuilder()
+            .ethosu_compile_spec(
+                "ethos-u55-128",
+                system_config="Ethos_U55_High_End_Embedded",
+                memory_mode="Shared_Sram",
+                extra_flags="--debug-force-regor --output-format=raw",
+            )
+            .set_permute_memory_format(args.model_name in MODEL_NAME_TO_MODEL.keys())
+            .set_quantize_io(True)
+        )
+    elif target == "ethos-u85-128":
+        return (
+            ArmCompileSpecBuilder()
+            .ethosu_compile_spec(
+                "ethos-u85-128",
+                system_config="Ethos_U85_SYS_DRAM_Mid",
+                memory_mode="Shared_Sram",
+                extra_flags="--output-format=raw",
+            )
+            .set_permute_memory_format(True)
+        )
+
+
 if __name__ == "__main__":
     parser = argparse.ArgumentParser()
     parser.add_argument(
@@ -175,6 +206,7 @@ def forward(self, x):
         action="store",
         required=False,
         default="ethos-u55-128",
+        choices=targets,
         help=f"For ArmBackend delegated models, pick the target, and therefore the instruction set generated. valid targets are {targets}",
     )
     parser.add_argument(
@@ -256,39 +288,7 @@ def forward(self, x):
     # be specified.
     compile_spec = None
     if args.delegate is True:
-        if args.target == "TOSA":
-            compile_spec = (
-                ArmCompileSpecBuilder()
-                .tosa_compile_spec()
-                .set_permute_memory_format(True)
-            )
-        elif args.target == "ethos-u55-128":
-            compile_spec = (
-                ArmCompileSpecBuilder()
-                .ethosu_compile_spec(
-                    "ethos-u55-128",
-                    system_config="Ethos_U55_High_End_Embedded",
-                    memory_mode="Shared_Sram",
-                    extra_flags="--debug-force-regor --output-format=raw",
-                )
-                .set_permute_memory_format(
-                    args.model_name in MODEL_NAME_TO_MODEL.keys()
-                )
-                .set_quantize_io(True)
-            )
-        elif args.target == "ethos-u85-128":
-            compile_spec = (
-                ArmCompileSpecBuilder()
-                .ethosu_compile_spec(
-                    "ethos-u85-128",
-                    system_config="Ethos_U85_SYS_DRAM_Mid",
-                    memory_mode="Shared_Sram",
-                    extra_flags="--output-format=raw",
-                )
-                .set_permute_memory_format(True)
-            )
-        else:
-            raise RuntimeError(f"Expected a target in {targets}, found {args.target}")
+        compile_spec = get_compile_spec(args.target)
         if args.intermediates is not None:
             compile_spec.dump_intermediate_artifacts_to(args.intermediates)
         compile_spec = compile_spec.build()