/in/foo.cc: In member function 'void BigIntArray::sort()':
/in/foo.cc:41:36: error: no matching function for call to 'BigIntArray::sort(std::vector<BigInt>::iterator, std::vector<BigInt>::iterator)'
         sort(arr.begin(), arr.end());
                                    ^
/in/foo.cc:40:10: note: candidate: void BigIntArray::sort()
     void sort() {
          ^~~~
/in/foo.cc:40:10: note:   candidate expects 0 arguments, 2 provided