Method AddLibrarySubset

parser/parser.cc:1762–1774

  }

  absl::Status AddLibrarySubset(cel::ParserLibrarySubset subset) override {
    if (subset.library_id.empty()) {
      return absl::InvalidArgumentError("subset must have a library id");
    }
    std::string library_id = subset.library_id;
    auto [it, inserted] =
        library_subsets_.insert({library_id, std::move(subset)});
    if (!inserted) {
      return absl::AlreadyExistsError(
          absl::StrCat("parser library subset already exists: ", library_id));
    }
    return absl::OkStatus();
  }

  absl::StatusOr<std::unique_ptr<cel::Parser>> Build() override {
    using std::swap;