list<T>& operator=(const list<T>& other) {
  // Remove any existing nodes we hold
  while(head != nullptr) {
    node<T>* toDelete = head;
    head = head->next;
    delete toDelete;
  }
  // Copy over data from the other list's nodes
  node<T>* current = other.head;
  if(current == nullptr)
    tail = nullptr;
  else {
    head = tail = new node<T>(current->data);
    current = current->next;
    while(current != nullptr) {
      tail->next = new node<T>(current->data);
      tail = tail->next;
      current = current->next;
    }
  }
  // operator= must always end with:
  return *this;
}