Can not support std::vector<std::string> ？

[consolexinhun]

#include <iostream>
#include <vector>
#include "cmdline.h"

int main(int argc, char** argv) {
  cmdline::parser parser;

  parser.add<std::vector<std::string>>("topics", 't', "topics to filter", true);

  parser.parse(argc, argv);

  std::vector<std::string> topics = parser.get<std::vector<std::string>>("topics");

  std::cout << "Topics to filter:" << std::endl;
  for (const auto& topic : topics) {
    std::cout << "- " << topic << std::endl;
  }

  return 0;
}

this code is compile error，how to support for std::vectorstd::string？