What is the correct way to type hint a homogenous Queue in Python3.6 (especially for PyCharm)?

Question

I'm writing a fractal generator in Python 3.6, and I use multiprocessing.Queues to pass messages from the main thread to the workers. This is what I've tried so far, but PyCharm doesn't seem to be able to infer attribute types for items taken from the queues:

from typing import NamedTuple, Any, Generic, TypeVar, Tuple
from multiprocessing import Process, Queue

T = TypeVar()


class Message(NamedTuple):
    method: str
    id: str
    data: Any = None


class TypedQueue(Generic[T]):
    def get(self) -> T:
        ...
    def put(self, m: T) -> None:
        ...


MessageQ = TypedQueue[Message]


class FractalWorker(Process):
    def __init__(self, work: MessageQ, results: MessageQ)
        super().__init__()
        self.work = work
        self.results = results

    @staticmethod
    def make_queues() -> Tuple[MessageQ, MessageQ]:
        work = cast(MessageQ, Queue())
        results = cast(MessageQ, Queue())
        return work, results

I want PyCharm to be able to tell that the attributes of the result of self.work.get have the types specified by the Message class. I also want to know if there is a standard way of type hinting Queues similar to this.

Answer 1

TypeVar should have a name.

T = TypeVar("T") fixes the problem.