[Python] Using Enum values as type variables, without using Literal

I'm trying to represent physical dimensions (length, time, temperature, ...), and cannot find a nice way to do so, that is compatible with type hinting and generics.

Ideally, I want to be able to define an Enum whose names are types themselves (a metaenum ?):

from enum import Enum

class Dim(Enum):
TIME = "t"
MASS = "m"


I can type hint dimensions (dim: Dim) but cannot do things like

from typing import Generic, TypeVar

T = TypeVar("T", bound=Dim) # only accepts `Dim`

class PhysicalQuantity(Generic[T]):
pass

class Container:
some_time: PhysicalQuantity[Dim.TIME] # doesn't work


because these are values.

Is there a construct as simple as Enum, but to make types instead of values ?

Reasons why I want to keep Enum:

• very easy to define
• very easy to associate to a value (str)
• Ability to sort of "think of Dim as the type, and Dim.TIME as a subtype"

There are functional solutions, however I'm asking this to get a "best way" more than a "working way". Here's what I found:

1. 
   The simplest solution is to do use Literal: SomeGenericType[Literal[Dim.TIME]], but this is both annoying to write each time and counter-intuitive for people who expect Dim.TIME to behave as a type.
   
   
2. 
   Switching to classes, the most intuitive idea:
   
   class Dimension:
   pass
   
   class TIME(Dimension):
   pass
   
   
   doesn't work, because I want type(TIME) to be Dim, to reproduce Enum behavior
   
   
3. 
   That leads to using a metaclass:
   
   class Dimension(type):
   # ... complete __init__ and __new__ to get TIME.symbol = "t"
   
   class TIME(metaclass=Dimension, symbol="t"):
   pass
   
   
   This works, but I lose the ability to do Dim.TIME, to get Dim.TIME from Dim('t'), ...
   

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