How to use the cfgrib.dataset.DatasetBuildError function in cfgrib

def test_dict_merge():
    master = {'one': 1}
    dataset.dict_merge(master, {'two': 2})
    assert master == {'one': 1, 'two': 2}
    dataset.dict_merge(master, {'two': 2})
    assert master == {'one': 1, 'two': 2}

    with pytest.raises(dataset.DatasetBuildError):
        dataset.dict_merge(master, {'two': 3})

def test_enforce_unique_attributes():
    assert dataset.enforce_unique_attributes({'key': [1]}, ['key'])
    assert not dataset.enforce_unique_attributes({'key': ['undef']}, ['key'])

    with pytest.raises(dataset.DatasetBuildError):
        assert dataset.enforce_unique_attributes({'key': [1, 2]}, ['key'])

squeeze=squeeze,
                read_keys=read_keys,
                time_dims=time_dims,
            )
        except DatasetBuildError as ex:
            # NOTE: When a variable has more than one value for an attribute we need to raise all
            #   the values in the file, not just the ones associated with that variable. See #54.
            key = ex.args[1]
            error_message = "multiple values for unique key, try re-open the file with one of:"
            fbks = []
            for value in index[key]:
                fbk = {key: value}
                fbk.update(filter_by_keys)
                fbks.append(fbk)
                error_message += "\n    filter_by_keys=%r" % fbk
            raise DatasetBuildError(error_message, key, fbks)
        short_name = data_var.attributes.get('GRIB_shortName', 'paramId_%d' % param_id)
        var_name = data_var.attributes.get('GRIB_cfVarName', 'unknown')
        if 'parameter' in encode_cf and var_name not in ('undef', 'unknown'):
            short_name = var_name
        try:
            dict_merge(variables, coord_vars)
            dict_merge(variables, {short_name: data_var})
            dict_merge(dimensions, dims)
        except ValueError:
            if errors == 'ignore':
                pass
            elif errors == 'raise':
                raise
            else:
                log.exception("skipping variable: paramId==%r shortName=%r", param_id, short_name)
    encoding = {

def dict_merge(master, update):
    for key, value in update.items():
        if key not in master:
            master[key] = value
        elif master[key] == value:
            pass
        else:
            raise DatasetBuildError(
                "key present and new value is different: "
                "key=%r value=%r new_value=%r" % (key, master[key], value)
            )

def enforce_unique_attributes(index, attributes_keys, filter_by_keys={}):
    # type: (messages.FileIndex, T.Sequence[str], dict) -> T.Dict[str, T.Any]
    attributes = collections.OrderedDict()  # type: T.Dict[str, T.Any]
    for key in attributes_keys:
        values = index[key]
        if len(values) > 1:
            fbks = []
            for value in values:
                fbk = {key: value}
                fbk.update(filter_by_keys)
                fbks.append(fbk)
            raise DatasetBuildError("multiple values for key %r" % key, key, fbks)
        if values and values[0] not in ('undef', 'unknown'):
            attributes['GRIB_' + key] = values[0]
    return attributes