def get_func(self, op_lookup: str) -> Callable:
        """
        Given a op type key, return the according translation function.
        Note that we will not distinguish in-place and functional,
        since we mostly use functional CoreML ops to translate.
        For instance, ``sub_`` -> ``sub``
        """
        op_lookup = sanitize_op_kind(op_lookup)
        op_lookup = unify_inplace_and_functional(op_lookup)
        return self.name_to_func_mapping.get(op_lookup, None)

        Given a op type key, return the according translation function.
        Note that we will not distinguish in-place and functional,
        since we mostly use functional CoreML ops to translate.
        For instance, ``sub_`` -> ``sub``
        
coremltools/converters/mil/frontend/torch/torch_op_registry.py