def get_lower_func(op_type: str) -> Callable:
        """Get the complex dialect op's lowering function."""
        if not LowerComplex.has_lower_func(op_type):
            raise ValueError(f"The op {op_type} doesn't have any lowering function registered.")
        return LowerComplex._lower_map[op_type]
Get the complex dialect op's lowering function.
coremltools/converters/mil/mil/passes/defs/lower_complex_dialect_ops.py