Parameterized Generics and TypeVar

Example list[T], since T being a type T chosen or limited by the bound
Use the following syntax: number = TypeVar('number', float, Decimal, Fraction) and del mode(data: Iterable[number] -> number) in that case I can assign number to T
Using bound to limit the types accepted

from collections import Counter
from collections.abc import Iterable, Hashable
from typing import TypeVar
HashableT = TypeVar('HashableT', bound=Hashable)
def mode(data: Iterable[HashableT]) -> HashableT:
    pairs = Counter(data).most_common(1)
    if len(pairs) == 0:
        raise ValueError('no mode for empty data')
    return pairs[0][0]

Code above states that Hashable and its subtypes are acceptable
Special types that accept any strings:

AnyVar = TypeVar(`AnyVar`, bytes, str)