4.4.1 traceback with python 3.5.2

[adam-stokes]

Describe the bug

4.4.1 ends in traceback with python 3.5.x

    from multidict import istr
  File "/run/code/.tox/py3/lib/python3.5/site-packages/multidict/__init__.py", line 18, in <module>
    from ._abc import MultiMapping, MutableMultiMapping
  File "/run/code/.tox/py3/lib/python3.5/site-packages/multidict/_abc.py", line 37, in <module>
    class MutableMultiMapping(MultiMapping[_T], MutableMapping[str, _T]):
  File "/run/code/.tox/py3/lib/python3.5/site-packages/multidict/_abc.py", line 44, in MutableMultiMapping
    def extend(self, *args: _Arg[_T], **kwargs: _T) -> None:
  File "/usr/lib/python3.5/typing.py", line 546, in __getitem__
    "Cannot subscript an existing Union. Use Union[u, t] instead.")
TypeError: Cannot subscript an existing Union. Use Union[u, t] instead.

To Reproduce

Expected behavior

Logs/tracebacks

Your version of the Python

3.5.2

Your version of the multidict distribution

4.4.1

Additional context

[sergeychibunin]

I have the same bug.

ubuntu 16.04
python 3.5.2

[asvetlov]

The problem was fixed by Python 3.5.3
Please upgrade python version or use older multidict instead

[webknjaz]

https://github.com/aio-libs/multidict/blob/master/setup.py#L272 let's update this then

[asvetlov]

Give me some time.
Maybe we can keep old pythons support

[asvetlov]

Fixed by #289