How to use the pyleri.THIS function in pyleri

ReKeywordsChangedError,
    NameAssignedError,
    MissingStartError,
    UnusedElementError)  # nopep8
from examples import JsonGrammar  # nopep8


class _TestGrammar1(Grammar):
    k_test = Keyword('test')
    k_ignore_case = Keyword('ignore_case', ign_case=True)
    START = Sequence(k_test, k_ignore_case)


class _TestGrammar2(Grammar):
    k_ni = Keyword('ni')
    s_seq = Sequence('(', THIS, ')')
    START = Prio(
        k_ni,
        s_seq,
        Sequence(THIS, Keyword('and'), THIS),
        Sequence(THIS, Keyword('or'), THIS))


class _TestGrammar3(Grammar):
    s_tic_tac = Sequence(Keyword('tic'), Keyword('tac'))
    s_tic_tac_toe = Sequence(Keyword('tic'), Keyword('tac'), Keyword('toe'))

    START = Sequence(
        Choice(s_tic_tac, s_tic_tac_toe),
        Choice(s_tic_tac, s_tic_tac_toe, most_greedy=False))

from examples import JsonGrammar  # nopep8


class _TestGrammar1(Grammar):
    k_test = Keyword('test')
    k_ignore_case = Keyword('ignore_case', ign_case=True)
    START = Sequence(k_test, k_ignore_case)


class _TestGrammar2(Grammar):
    k_ni = Keyword('ni')
    s_seq = Sequence('(', THIS, ')')
    START = Prio(
        k_ni,
        s_seq,
        Sequence(THIS, Keyword('and'), THIS),
        Sequence(THIS, Keyword('or'), THIS))


class _TestGrammar3(Grammar):
    s_tic_tac = Sequence(Keyword('tic'), Keyword('tac'))
    s_tic_tac_toe = Sequence(Keyword('tic'), Keyword('tac'), Keyword('toe'))

    START = Sequence(
        Choice(s_tic_tac, s_tic_tac_toe),
        Choice(s_tic_tac, s_tic_tac_toe, most_greedy=False))


class _TestGrammar4(Grammar):
    START = Ref()
    ni_item = Choice(Keyword('ni'), START)
    START = Sequence('[', List(ni_item), ']')

k_alter,
        most_greedy=False)

    _boolean = Choice(k_true, k_false, most_greedy=False)

    log_keywords = Choice(
        k_debug,
        k_info,
        k_warning,
        k_error,
        k_critical,
        most_greedy=False)

    int_expr = Prio(
        r_integer,
        Sequence('(', THIS, ')'),
        Sequence(THIS, Tokens('+ - * % /'), THIS))

    string = Choice(r_singleq_str, r_doubleq_str, most_greedy=False)

    time_expr = Prio(
        r_time_str,
        k_now,
        string,
        r_integer,
        Sequence('(', THIS, ')'),
        Sequence(THIS, Tokens('+ - * % /'), THIS))

    series_columns = List(Choice(
        k_name,
        k_type,
        k_length,

k_address,
            k_buffer_path,
            k_dbpath,
            k_ip_support,
            k_libuv,
            k_name,
            k_uuid,
            k_version,
            k_status,
            k_reindex_progress,
            k_sync_progress,
            k_tee_pipe_name,
            most_greedy=False), str_operator, string),
        Sequence(k_online, bool_operator, _boolean),
        Sequence(k_log_level, int_operator, log_keywords),
        Sequence('(', THIS, ')'),
        Sequence(THIS, k_and, THIS),
        Sequence(THIS, k_or, THIS)))

    # where shard
    where_shard = Sequence(k_where, Prio(
        Sequence(
            Choice(k_sid, k_pool, k_size, most_greedy=False),
            int_operator,
            int_expr),
        Sequence(Choice(k_server, k_status), str_operator, string),
        Sequence(
            Choice(k_start, k_end, most_greedy=False),
            int_operator,
            time_expr),
        Sequence(
            k_type,