generic_property.py

from typing import TypeVar, Generic

 T = TypeVar('T', bound=str) # T is str or subtype of str

 class Stack(Generic[T]):
     def __init__(self, initial_items: list[T]=None) -> None:
         if not initial_items:
             initial_items = []
         self.items: list[T] = initial_items

     def push(self, item: T) -> None:
         self.items.append(item)

     def pop(self) -> T:
         return self.items.pop()

     @property
     def first(self) -> T:
         return self.items[0]

 s1 = Stack[str]()
 s1.push('A')
 b1 = s1.items[0].endswith('Z') # bool | Any

 s2 = Stack() # default type
 s2.push('B')
 b2 = s2.items[0].endswith('Z') # bool | Any

 s3 = Stack[str]()
 s3.push('C')
 b3 = s3.first.endswith('Z') # bool

 s4 = Stack() # default type with property
 s4.push('D')
 b4 = s4.first.endswith('Z') # Any (Why??)