
"""simple docstring"""





from __future__ import annotations

from collections.abc import Iterator
from typing import Any


class A_			:




  '''simple docstring'''







  def __init__(	self       ,     lowercase_						):

     """simple docstring"""
     UpperCAmelCase_      :      Any      =					data
     UpperCAmelCase_      :      Node | None      =					None







  def __str__(	self						):

     """simple docstring"""
     return F"""{self.data}"""




class A_			:




  '''simple docstring'''







  def __init__(	self						):

     """simple docstring"""
     UpperCAmelCase_      :      Node | None      =					None
     UpperCAmelCase_      :      Node | None      =					None







  def __iter__(	self						):

     """simple docstring"""
     UpperCAmelCase_      :      Tuple      =					self.front
     while node:
        yield node.data
        UpperCAmelCase_      :      Dict      =					node.next







  def __len__(	self						):

     """simple docstring"""
     return len(tuple(iter(self						)						)						)







  def __str__(	self						):

     """simple docstring"""
     return " <- ".join(str(lowercase_						) for item in self						)







  def  UpperCamelCase__      (	self						):

     """simple docstring"""
     return len(self						) == 0







  def  UpperCamelCase__      (	self       ,     lowercase_						):

     """simple docstring"""
     UpperCAmelCase_      :      Dict      =					Node(lowercase_						)
     if self.is_empty():
        UpperCAmelCase_      :      int      =					node
     else:
        assert isinstance(self.rear       ,     lowercase_						)
        UpperCAmelCase_      :      Optional[int]      =					node
        UpperCAmelCase_      :      Any      =					node







  def  UpperCamelCase__      (	self						):

     """simple docstring"""
     if self.is_empty():
        raise IndexError("dequeue from empty queue"						)
     assert isinstance(self.front       ,     lowercase_						)
     UpperCAmelCase_      :      int      =					self.front
     UpperCAmelCase_      :      Optional[Any]      =					self.front.next
     if self.front is None:
        UpperCAmelCase_      :      List[Any]      =					None
     return node.data







  def  UpperCamelCase__      (	self						):

     """simple docstring"""
     UpperCAmelCase_      :      Optional[Any]      =					None


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

    testmod()




"""simple docstring"""





from __future__ import annotations

from typing import Any


class A_			:




  '''simple docstring'''







  def __init__(	self       ,     lowercase_       ,     lowercase_						):  # noqa: A002

     """simple docstring"""
     UpperCAmelCase_      :      Optional[Any]      =					item
     UpperCAmelCase_      :      Optional[Any]      =					next




class A_			:




  '''simple docstring'''







  def __init__(	self						):

     """simple docstring"""
     UpperCAmelCase_      :      Node | None      =					None
     UpperCAmelCase_      :      Optional[int]      =					0







  def  UpperCamelCase__      (	self       ,     lowercase_						):

     """simple docstring"""
     UpperCAmelCase_      :      int      =					Node(lowercase_       ,     self.head						)
     self.size += 1







  def  UpperCamelCase__      (	self						):

     """simple docstring"""
     # Switched 'self.is_empty()' to 'self.head is None'
     # because mypy was considering the possibility that 'self.head'
     # can be None in below else part and giving error
     if self.head is None:
        return None
     else:
        UpperCAmelCase_      :      int      =					self.head.item
        UpperCAmelCase_      :      str      =					self.head.next
        self.size -= 1
        return item







  def  UpperCamelCase__      (	self						):

     """simple docstring"""
     return self.head is None







  def __str__(	self						):

     """simple docstring"""
     if self.is_empty():
        return ""
     else:
        UpperCAmelCase_      :      str      =					self.head
        UpperCAmelCase_      :      str      =					""
        UpperCAmelCase_      :      list[str]      =					[]
        while iterate:
           item_list.append(str(iterate.item						)						)
           UpperCAmelCase_      :      Tuple      =					iterate.next

        UpperCAmelCase_      :      Optional[Any]      =					" --> ".join(lowercase_						)

        return item_str







  def __len__(	self						):

     """simple docstring"""
     return self.size


