[Core] inrtoduce ModelWrapper.get_customop_wrapper

grabs CustomOp instance with the right opset version from protobuf
imported opsets

Author: maltanar

src/qonnx/core/modelwrapper.py

@@ -39,7 +39,7 @@
 import qonnx.util.basic as util
 import qonnx.util.onnx as onnxutil
 from qonnx.core.datatype import DataType
-from qonnx.custom_op.registry import is_custom_op
+from qonnx.custom_op.registry import getCustomOp, is_custom_op
 from qonnx.transformation.double_to_single_float import DoubleToSingleFloat
 from qonnx.transformation.general import (
     RemoveStaticGraphInputs,
@@ -742,3 +742,10 @@ def set_tensor_sparsity(self, tensor_name, sparsity_dict):
     def get_opset_imports(self):
         """Returns a list of imported opsets as a {domain, version} dictionary."""
         return {opset.domain: opset.version for opset in self._model_proto.opset_import}
+
+    def get_customop_wrapper(self, node):
+        """Return CustomOp instance for given node, respecting the
+        imported opset version in the model protobuf."""
+        opset_imports = self.get_opset_imports()
+        opset_import = opset_imports[node.domain]
+        return getCustomOp(node, onnx_opset_version=opset_import)