Refactoring suggestion to apply the `import typing as t` convention

[jamilraichouni]

Hi,

To avoid to have to maintain unnecessary long import lists like this:

opcua-asyncio/asyncua/client/client.py

Line 6 in ea64b64

from typing import Any, Callable, Coroutine, Dict, Iterable, List, Optional, Sequence, Tuple, Type, Union, cast

I suggest that you always do

import typing as t

and then refer to types via t.(...) like t.Iterable etc. which is a nice trick.

All best,
Jamil