```
$ ~/arc/build/clickhouse/programs/clickhouse client
ClickHouse client version 21.2.1.1-arcadia.
Connecting to localhost:9000 as user default.
Connected to ClickHouse server version 21.2.1 revision 54447.

max42-dev.sas.yp-c.yandex.net :) create table t(a Tuple(UInt8, UInt8)) engine = Log()

CREATE TABLE t
(
    `a` Tuple(UInt8, UInt8)
)
ENGINE = Log

Query id: b49dbb5d-d2a9-4c99-b90e-00c60edf2103

Ok.

0 rows in set. Elapsed: 0.005 sec. 

max42-dev.sas.yp-c.yandex.net :) insert into t values ((NULL, 42))

INSERT INTO t VALUES

Query id: 318d6f3e-f3bc-467c-85ff-62da908230dd

Logical error: 'Unexpected literal type inside Array: Nothing. It's a bug'.
Aborted (core dumped)
```

This is CH similar to one from Arcadia r7788360 (~fresh master version from GH).

(you don't have to strictly follow this form)

{
    skipWhitespaceIfAny(buf);
    if (likely(column_idx + 1 != num_columns))
        return checkChar(',', buf);
    else
        return checkChar(')', buf);
}
bool ValuesBlockInputFormat::shouldDeduceNewTemplate(size_t column_idx)
{
    if (!format_settings.values.deduce_templates_of_expressions)
        return false;
    
    
    
    float attempts_weighted = 1.5 * attempts_to_deduce_template[column_idx] +  0.5 * attempts_to_deduce_template_cached[column_idx];
    constexpr size_t max_attempts = 100;
    if (attempts_weighted < max_attempts)
        return true;
    if (rows_parsed_using_template[column_idx] / attempts_weighted > 1)
    {
        
        attempts_to_deduce_template[column_idx] = 0;
        attempts_to_deduce_template_cached[column_idx] = 0;
        rows_parsed_using_template[column_idx] = 0;
        return true;
    }
    return false;
}
void ValuesBlockInputFormat::readPrefix()