code: def convert_layer(node, **kwargs):
          
          op = str(node["op"])
          if op not in MXNetGraph.registry_:
              raise AttributeError("No conversion function registered for op type %s yet." % op)
          convert_func = MXNetGraph.registry_[op]
          return convert_func(node, **kwargs)
docs: Convert MXNet layer to ONNX