#include <iostream>
#include <string>
#include <stdexcept>
 
void getMusic(const std::string & key) {
    if(key.compare("") == 0) throw std::invalid_argument("empty key");
}
 
int main() {
	try {
	    getMusic("");
	} catch (const std::runtime_error &ob) {
	    std::cout << ob.what() << std::endl;
	} catch (const std::invalid_argument &ob) {
	    std::cout << ob.what() << std::endl;
	} catch (...) {
	    std::cout << "unknown error\n";
	}
	return 0;
}

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