**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')))). 
```

addAttributeSize<Float32>(attribute);
                break;
            case AttributeUnderlyingType::utFloat64:
                addAttributeSize<Float64>(attribute);
                break;
            case AttributeUnderlyingType::utDecimal32:
                addAttributeSize<Decimal32>(attribute);
                break;
            case AttributeUnderlyingType::utDecimal64:
                addAttributeSize<Decimal64>(attribute);
                break;
            case AttributeUnderlyingType::utDecimal128:
                addAttributeSize<Decimal128>(attribute);
                break;
            case AttributeUnderlyingType::utString:
            {
                addAttributeSize<StringRef>(attribute);
                bytes_allocated += sizeof(Arena) + attribute.string_arena->size();
                break;
            }
        }
    }
}
template <typename T>
void IPAddressDictionary::createAttributeImpl(Attribute & attribute, const Field & null_value)
{
    attribute.null_values = T(null_value.get<NearestFieldType<T>>());
    attribute.maps.emplace<ContainerType<T>>();
}
IPAddressDictionary::Attribute IPAddressDictionary::createAttributeWithType(const AttributeUnderlyingType type, const Field & null_value)