How to use the pydsdl.read_namespace function in pydsdl

...     import uavcan.si.sample.volumetric_flow_rate
    ... except (ImportError, AttributeError):
    ...     _ = pyuavcan.dsdl.generate_package(root_namespace_directory='tests/dsdl/namespaces/sirius_cyber_corp',
    ...                                        lookup_directories=['tests/public_regulated_data_types/uavcan'],
    ...                                        output_directory=dsdl_generated_dir)
    ...     _ = pyuavcan.dsdl.generate_package(root_namespace_directory='tests/public_regulated_data_types/uavcan',
    ...                                        output_directory=dsdl_generated_dir)
    ...     importlib.invalidate_caches()
    ...     import sirius_cyber_corp
    ...     import uavcan.si.sample.volumetric_flow_rate
    """
    # Read the DSDL definitions
    if isinstance(lookup_directories, (str, bytes)):
        # https://forum.uavcan.org/t/nestedrootnamespaceerror-in-basic-usage-demo/794
        raise TypeError(f'Lookup directories shall be an iterable of strings, not {type(lookup_directories).__name__}')
    composite_types = pydsdl.read_namespace(root_namespace_directory=str(root_namespace_directory),
                                            lookup_directories=list(map(str, lookup_directories or [])),
                                            allow_unregulated_fixed_port_id=allow_unregulated_fixed_port_id)
    root_namespace_name, = set(map(lambda x: x.root_namespace, composite_types))  # type: str,

    # Template primitives
    filters = {
        'pickle':            _pickle_object,
        'numpy_scalar_type': _numpy_scalar_type,
    }

    tests = {
        'PaddingField': lambda x: isinstance(x, pydsdl.PaddingField),
        'saturated':    _test_if_saturated,
    }

    # Generate code