fix some cython code

engines/__init__.py

@@ -1,3 +1,7 @@
+import platform
+import sys
+
+
 def _check_tensor_gpu_index():
     try:
         import pynvml
@@ -21,12 +25,28 @@ def _check_tensor_gpu_index():
             pass
 
 
+def _is_apple_silicon():
+    if sys.platform != "darwin" or platform.machine() != "arm64":
+        return False
+    try:
+        import coremltools
+        return True
+    except ImportError:
+        return False
+
+
 tensor_gpu_index = _check_tensor_gpu_index()
 
 
-def create_engine(model_bytes: bytes, batch_size: int = 1):
+def _select_engine_class():
     if tensor_gpu_index > -1:
         from engines.tensorrt_engine import TensorRTEngine
-        return TensorRTEngine(model_bytes, batch_size)
+        return TensorRTEngine
+    if _is_apple_silicon():
+        from engines.coreml_engine import CoreMLEngine
+        return CoreMLEngine
     from engines.onnx_engine import OnnxEngine
-    return OnnxEngine(model_bytes, batch_size)
+    return OnnxEngine
+
+
+EngineClass = _select_engine_class()