from __future__ import annotations

from collections.abc import Iterator
from typing import Any



class 						snake_case_ :






   def __init__(   self       :  str			,		lowercase_       :  Any						)      ->		Union[str, Any]:
       lowercase__				:     Union[str, Any]					      =       data
       lowercase__				:     List[str]					      =       None







   def __str__(   self       :  Optional[int]						)      ->		Optional[int]:
       return F'''{self.data}'''



class 						snake_case_ :






   def __init__(   self       :  List[str]						)      ->		Dict:
       lowercase__				:     str					      =       None
       lowercase__				:     List[Any]					      =       None






   def __iter__(   self       :  List[Any]						)      ->		List[str]:
       lowercase__				:     Optional[Any]					      =       self.front
       while node:
           yield node.data
           lowercase__				:     List[Any]					      =       node.next






   def __len__(   self       :  Dict						)      ->		Dict:
       return len(tuple(iter(self						)						)						)






   def __str__(   self       :  Tuple						)      ->		int:
       return " <- ".join(str(lowercase_						) for item in self						)






   def    __UpperCamelCase  (   self       :  List[str]						)      ->		Tuple:
       return len(self						) == 0






   def    __UpperCamelCase  (   self       :  Optional[int]			,		lowercase_       :  Any						)      ->		Tuple:
       lowercase__				:     Union[str, Any]					      =       Node(lowercase_						)
       if self.is_empty():
           lowercase__				:     Union[str, Any]					      =       node
       else:
           assert isinstance(self.rear			,		lowercase_						)
           lowercase__				:     Dict					      =       node
           lowercase__				:     int					      =       node






   def    __UpperCamelCase  (   self       :  List[str]						)      ->		Optional[int]:







       if self.is_empty():
           raise IndexError("dequeue from empty queue"						)
       assert isinstance(self.front			,		lowercase_						)
       lowercase__				:     Dict					      =       self.front
       lowercase__				:     Dict					      =       self.front.next
       if self.front is None:
           lowercase__				:     Any					      =       None
       return node.data







   def    __UpperCamelCase  (   self       :  List[Any]						)      ->		Any:
       lowercase__				:     Union[str, Any]					      =       None


if __name__ == "__main__":
      from doctest import testmod

      testmod()




from typing import Callable

def     lowercase_       (    _lowerCamelCase							: Callable):

    def wrapper(_lowerCamelCase							: str):
        lowercase__				:     Tuple					      =       function_with_docstring.__doc__
        return target_function

    return wrapper



