int start = a_randomizer.inclusive(0, testers[index]->length());
int end = a_randomizer.inclusive(0, testers[index]->length());
flip_increasing(start, end);
int start = a_randomizer.inclusive(0, testers[index]->length());
int end = a_randomizer.inclusive(0, testers[index]->length());
flip_increasing(start, end);