in blogs/sept-2021/converter.cc [43:50]
int64_t TryGetInteger(const std::map<Variant, Variant>& from, const char* key) {
auto it = from.find(Variant(key));
if (it == from.end() || !it->second.is_int64()) {
return 0;
}
return it->second.int64_value();
}