View Compilation Error

0_0_39413576_2064.cpp: In function 'void test()':
0_0_39413576_2064.cpp:43:31: error: no matching function for call to 'KMP::fnex()'
   43 |     vector<int> nex = kmp.fnex();
      |                       ~~~~~~~~^~
0_0_39413576_2064.cpp:17:24: note: candidate: 'static std::vector<int> KMP::fnex(std::string&)'
   17 |     static vector<int> fnex(string &s){
      |                        ^~~~
0_0_39413576_2064.cpp:17:24: note:   candidate expects 1 argument, 0 provided