text: from typing import Any, Iterator, Optional, Sequence, T, Union
  from collections import deque
  
  class LinkedList(Sequence[T]):
      def __init__(self, value: T, next: Optional['LinkedList[T]']=None):
          self.value: T = value
          self.next: Union[LinkedList[T], None] = next
  
      def final(self) -> 'LinkedList[T]':
          return deque(self.__iter__(), 1).pop()
  
      def __getitem__(self, key: int) -> 'LinkedList[T]':
          try:
              it = iter(self)
              for _ in range(key):
                  next(it)
              return next(it)
          except StopIteration:
              raise IndexError(f"{self.__class__.__qualname__} index '{key}' out of range") from None
  
      def __setitem__(self, key: int, value: 'LinkedList[T]') -> 'LinkedList[T]':
          try:
              it = iter(self)
              for _ in range(key-1):
                  next(it)
              p = next(it)
              if c := next(it, False):
                  value.next = c.next
              p.next = value
              return c
          except StopIteration:
              raise IndexError(f"{self.__class__.__qualname__} index '{key}' out of range") from None
  
      def __delitem__(self, key: int) -> 'LinkedList[T]':
          try:
              it = iter(self)
              for _ in range(key-1):
                  next(it)
              p = next(it)
              if c := next(it, None):
                  p.next = c.next
              else:
                  p.next = None
              return c
          except StopIteration:
              raise IndexError(f"{self.__class__.__qualname__} index '{key}' out of range") from None
  
      def __bool__(self) -> True:
          return True
  
      def __len__(self) -> int:
          return sum(1 for _ in self)
          # Deal with circular lists
          t = 0
          for c in self:
              if c is self and t:
                  break
              t += 1
          return t
  
      def __add__(self, other: 'LinkedList[T]') -> 'LinkedList[T]':
          if not isinstance(other, LinkedList):
              raise TypeError
          end = other.final()
          end.next = self.next
          self.next = other
          return end
  
      def __iadd__(self, other: 'LinkedList[T]') -> 'LinkedList[T]':
          if not isinstance(other, LinkedList):
              raise TypeError
          end = other.final()
          end.next = self.next
          self.next = other
          return self
  
      def __iter__(self) -> Iterator['LinkedList[T]']:
          c = self
          yield c
          while c.next:
              c = c.next
              yield c
  
      def __repr__(self) -> str:
          return f"{self.__class__.__qualname__}<{self.value}: {'X' if self.next else 'O'}>"
  
      def index(self, item: 'LinkedList[T]') -> int:
          raise NotImplementedError
      def count(self, item: 'LinkedList[T]') -> int:
          raise NotImplementedError
  
  class LinkedView(Sequence[T]):
      def __init__(self, head: LinkedList[T], end: Union[int, LinkedList[T], None]=None, step: int=1):
          self.head = head
          self.end = end
          self.step = step
  
      def __getitem__(self, key: int) -> LinkedList[T]:
          return self.head.__getitem__(key * self.step)
      def __len__(self, key: int) -> LinkedList[T]:
          raise NotImplementedError
  
      def __iter__(self) -> Iterator[LinkedList[T]]:
          c = self.head
          yield c
          i = 0
          if isinstance(self.end, int):
              while c.next and (i+1) < self.end:
                  i += 1
                  c = c.next
                  if not (i % self.step):
                      yield c
          elif isinstance(self.end, LinkedList):
              while c.next and c.next != self.end:
                  i += 1
                  c = c.next
                  if not (i % self.step):
                      yield c
          else:
              while c.next:
                  i += 1
                  c = c.next
                  if not (i % self.step):
                      yield c
  
  class LinkedContainer(Sequence[T]):
      def __init__(self, head: LinkedList[T]):
          self.head = head
          self.end = self.head.final()
  
      def __getitem__(self, key: int) -> LinkedList[T]:
          return self.head.__getitem__(key)
      def __setitem__(self, key: int, value: LinkedList[T]) -> LinkedList[T]:
          if c:= self.head.__setitem__(key, value) and c is self.end:
              self.end = value
      def __delitem__(self, key: int) -> LinkedList[T]:
          if self.head.__delitem__(key) is self.end:
              self.end = self.head.final()
  
      def __len__(self) -> int:
          return self.head.__len__()
      def __iter__(self) -> Iterator[LinkedList[T]]:
          return self.head.__iter__()
  
      def __add__(self, other: 'LinkedContainer[T]') -> 'LinkedContainer[T]':
          if not isinstance(other, LinkedContainer):
              raise TypeError
          self.end = self.end + other.head
          return self
  
      def append(self, item: LinkedList[T]):
          self.end += item
  
  LinkedList.__qualname__ = "l"
  
  SIZE = 10
  e = f = LinkedList(0)
  for i in range(1, SIZE+1):
      e.next = LinkedList(i)
      e = e.next
  
  e = g = LinkedList(SIZE+1)
  for i in range(SIZE+1, 2*SIZE+1):
      e.next = LinkedList(i)
      e = e.next
  
  e = h = LinkedList(SIZE+1)
  for i in range(2*SIZE+1, 3*SIZE+1):
      e.next = LinkedList(i)
      e = e.next
  
  print("LinkedList F:", *f)
  print("LinkedList G:", *g)
  print("LinkedList H:", *h)
  print()
  
  # a = f + g + h
  
  f.final() + g
  v = LinkedView(f, -1, 2)
  print(*f)
  print(*v)
  