`check_requirements(('coremltools',))` (#4478)

.github/workflows/ci-testing.yml

@@ -48,7 +48,7 @@ jobs:
         run: |
           python -m pip install --upgrade pip
           pip install -qr requirements.txt -f https://download.pytorch.org/whl/cpu/torch_stable.html
-          pip install -q onnx
+          pip install -q onnx onnx-simplifier coremltools  # for export
           python --version
           pip --version
           pip list
@@ -76,5 +76,5 @@ jobs:
 
           python hubconf.py  # hub
           python models/yolo.py --cfg ${{ matrix.model }}.yaml  # inspect
-          python export.py --img 128 --batch 1 --weights ${{ matrix.model }}.pt  # export
+          python export.py --img 128 --batch 1 --weights ${{ matrix.model }}.pt --include onnx torchscript  # export
         shell: bash

export.py

@@ -87,6 +87,7 @@ def export_coreml(model, img, file):
     # CoreML model export
     prefix = colorstr('CoreML:')
     try:
+        check_requirements(('coremltools',))
         import coremltools as ct
 
         print(f'\n{prefix} starting export with coremltools {ct.__version__}...')