**Use case**
I'm using `ip_trie` on maxmind geoip databases. Given an IP address I want to find out what key was used (ie what network the IP comes under). But it seems it is not possible to look up the key field when using `dictGet`?

```
        <layout>
            <ip_trie/>
        </layout>
        <structure>
            <key>
                <attribute>
                    <name>network</name>
                    <type>String</type>
                </attribute>
            </key>
            <attribute>
                <name>geoname_id</name>
                <type>UInt32</type>
                <null_value>0</null_value>
            </attribute>
...
```

```
clickhouse :) select dictGet('geoip_city_blocks_ipv4', 'geoname_id', tuple(toUInt32(toIPv4('1.1.1.1')))) ;

┌─dictGet('geoip_city_blocks_ipv4', 'geoname_id', tuple(toUInt32(toIPv4('1.1.1.1'))))─┐
│                                                                             2077456 │
└─────────────────────────────────────────────────────────────────────────────────────┘

clickhouse :) select dictGet('geoip_city_blocks_ipv4', 'network', tuple(toUInt32(toIPv4('1.1.1.1')))) ;

Received exception from server (version 20.11.3):
Code: 36. DB::Exception: Received from localhost:9000. DB::Exception: No such attribute 'network': While processing dictGet('geoip_city_blocks_ipv4', 'network', tuple(toUInt32(toIPv4('1.1.1.1')))). 
```

mask_column.push_back(record.prefixIPv6());
            row_idx.push_back(record.row);
        }
    }
    else
    {
        auto deleted_count = sortAndUnique(ip_records,
            [](const auto & record_a, const auto & record_b)
            {
                UInt32 a = IPv4AsUInt32(record_a.addr.addr());
                UInt32 b = IPv4AsUInt32(record_b.addr.addr());
                if (a == b)
                    return compareTo(record_a.prefix, record_b.prefix);
                return compareTo(a, b);
            });
        if (deleted_count > 0)
            LOG_WARNING(logger, "removing {} non-unique subnets from input", deleted_count);
        auto & ipv4_col = ip_column.emplace<IPv4Container>();
        ipv4_col.reserve(ip_records.size());
        for (const auto & record : ip_records)
        {
            auto addr = IPv4AsUInt32(record.addr.addr());
            ipv4_col.push_back(addr);
            mask_column.push_back(record.prefix);
            row_idx.push_back(record.row);
        }
    }
    parent_subnet.resize(ip_records.size());
    std::stack<size_t> subnets_stack;
    for (const auto i : ext::range(0, ip_records.size()))