
'''simple docstring'''
from __future__ import annotations

from collections.abc import Iterator
from typing import Any






class 				UpperCAmelCase_			:





 def __init__(      self	,    lowercase_):
     snake_case_	:      Any            =  data
     snake_case_	:      Node | None            =  None





 def __str__(      self):
     return F'{self.data}'






class 				UpperCAmelCase_			:





 def __init__(      self):
     snake_case_	:      Node | None            =  None
     snake_case_	:      Node | None            =  None





 def __iter__(      self):
     snake_case_	:      Any            =  self.front
     while node:
         yield node.data
         snake_case_	:      Any            =  node.next





 def __len__(      self):
     return len(tuple(iter(self)))





 def __str__(      self):
     return " <- ".join(str(_snake_case) for item in self)





 def     snake_case__						(      self):
     return len(self) == 0





 def     snake_case__						(      self	,    lowercase_):
     snake_case_	:      Dict            =  Node(_snake_case)
     if self.is_empty():
         snake_case_	:      int            =  node
     else:
         assert isinstance(self.rear	,    _snake_case)
         snake_case_	:      str            =  node
         snake_case_	:      Union[str, Any]            =  node





 def     snake_case__						(      self):
     if self.is_empty():
         raise IndexError("dequeue from empty queue")
     assert isinstance(self.front	,    _snake_case)
     snake_case_	:      Union[str, Any]            =  self.front
     snake_case_	:      str            =  self.front.next
     if self.front is None:
         snake_case_	:      Any            =  None
     return node.data





 def     snake_case__						(      self):
     snake_case_	:      List[Any]            =  None


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

  testmod()






'''simple docstring'''
from __future__ import annotations

from typing import Any






class 				UpperCAmelCase_			:





 def __init__(      self	,    lowercase_	,    lowercase_):  # noqa: A002
     snake_case_	:      List[str]            =  item
     snake_case_	:      Dict            =  next






class 				UpperCAmelCase_			:





 def __init__(      self):
     snake_case_	:      Node | None            =  None
     snake_case_	:      List[str]            =  0





 def     snake_case__						(      self	,    lowercase_):
     snake_case_	:      List[Any]            =  Node(lowercase_	,    self.head)
     self.size += 1





 def     snake_case__						(      self):
     # 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:
         snake_case_	:      List[Any]            =  self.head.item
         snake_case_	:      Any            =  self.head.next
         self.size -= 1
         return item





 def     snake_case__						(      self):
     return self.head is None





 def __str__(      self):
     if self.is_empty():
         return ""
     else:
         snake_case_	:      Dict            =  self.head
         snake_case_	:      Optional[Any]            =  ""
         snake_case_	:      list[str]            =  []
         while iterate:
             item_list.append(str(iterate.item))
             snake_case_	:      List[str]            =  iterate.next

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

         return item_str





 def __len__(      self):
     return self.size




