Function require_i64_array

include/engine/framework/io/json.h:145–147

    const auto * value = object.find(key);
    return value != nullptr && value->is_string() ? value->as_string() : std::move(default_value);
}

inline std::string optional_nullable_string(const Value & object, const std::string & key, std::string default_value) {
    const auto * value = object.find(key);
    if (value == nullptr || value->is_null()) {
        return default_value;