void foldInitialElements() {}
void foldInitialSpread1() {}
void foldInitialSpread2([bool c = false]) {}
void foldInitialSpread3([bool c = false]) {}
void foldInitialSpread4([bool c = false]) {}
void foldInitialSpread5([bool c = false]) {}
void foldInitialSpread6([bool c = false]) {}
main() {}
void expect(List list1, List list2) {}