What is the correct way in python to annotate a path with type hints?

Question

What is the proper way to annotate this simple utility function in python3 that reads from a file? It should accept pathlib.Path objects as well as any other common way of passing a path.

def read_json(path: <TYPE HINT>):
    with open(path, 'rb') as f:
        data = json.load(f)
    return data

It seems to me as if this topic is in flux and I couldn't find a good place where this information was collected. I am interested in how to handle this in python 3.6, 3.7 and 3.8.

Solution

I assume that typical path objects are either Paths or strs, as such you could use a Union:

import pathlib
import typing

typing.Union[str, pathlib.Path]

Comments

[Martin Bonner supports Monica]

Is there anywhere the standard functions are shown with type annotations? I couldn't find one, but "copy the annotation for open would be a good answer.

[Diogo]

open uses file: _OpenFile as annotation, which is the union Union[AnyPath, int].

[maf88]

I use this PathLike = TypeVar("PathLike", str, pathlib.Path, None).