@Override
    public ClickHouseMapValue update(short value) {
        set(Collections.singletonMap(getDefaultKey(), valueType.cast(value)));
        return this;
    }
Update value of the given object or create a new instance if {@code ref} is
null.

@param ref       object to update, could be null
@param value     value
@param keyType   non-null class of key
@param valueType non-null class of value
@return same object as {@code ref} or a new instance if it's null
clickhouse-data/src/main/java/com/clickhouse/data/value/ClickHouseMapValue.java