How to use the cytoolz.functoolz.excepts function in cytoolz

def null_if_excepts(exc_type, fn):
    return excepts(
        exc_type,
        fn,
        static_return(None),
    )

apply_formatter_if(
                static_return(None),
                compose(is_null, operator.itemgetter('block_number')),
            ),
            call_eth_tester('get_transaction_receipt'),
        )),
        'getUncleByBlockHashAndIndex': not_implemented,
        'getUncleByBlockNumberAndIndex': not_implemented,
        'getCompilers': not_implemented,
        'compileLLL': not_implemented,
        'compileSolidity': not_implemented,
        'compileSerpent': not_implemented,
        'newFilter': create_log_filter,
        'newBlockFilter': call_eth_tester('create_block_filter'),
        'newPendingTransactionFilter': call_eth_tester('create_pending_transaction_filter'),
        'uninstallFilter': excepts(
            FilterNotFound,
            compose(
                is_null,
                call_eth_tester('delete_filter'),
            ),
            static_return(False),
        ),
        'getFilterChanges': null_if_filter_not_found(call_eth_tester('get_only_filter_changes')),
        'getFilterLogs': null_if_filter_not_found(call_eth_tester('get_all_filter_logs')),
        'getLogs': not_implemented,
        'getWork': not_implemented,
        'submitWork': not_implemented,
        'submitHashrate': not_implemented,
    },
    'db': {
        'putString': not_implemented,

def _get_yaml_map_comments(rawvalue):
        return dict((key, excepts(KeyError,
                                  lambda k: rawvalue.ca.items[k][2].value.strip() or None,
                                  lambda _: None  # default value on exception
                                  )(key))
                    for key in rawvalue)

def _get_yaml_list_comments(value):
        items = value.ca.items
        raw_comment_lines = tuple(excepts((AttributeError, KeyError, TypeError),
                                          lambda q: items.get(q)[0].value.strip() or None,
                                          lambda _: None  # default value on exception
                                          )(q)
                                  for q in range(len(value)))
        return raw_comment_lines