TypeError: This Callable type is already parameterized.

[IurmanJ]

Describe your environment

$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 16.04.6 LTS
Release:	16.04
Codename:	xenial

$ uname -r
4.13.0-45-generic

$ python3 --version
Python 3.5.2

Steps to reproduce

$ pip install opentelemetry-api
$ pip install opentelemetry-sdk
$ python3
>>> from opentelemetry import trace

What is the expected behavior?

Well, not that I guess.

What is the actual behavior?

>>> from opentelemetry import trace
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/justin/.local/lib/python3.5/site-packages/opentelemetry/trace/__init__.py", line 70, in <module>
    from opentelemetry.util import loader, types
  File "/home/justin/.local/lib/python3.5/site-packages/opentelemetry/util/loader.py", line 117, in <module>
    implementation_fn: _UntrustedImplFactory[_T], api_type: Type[_T]
  File "/usr/lib/python3.5/typing.py", line 815, in __getitem__
    raise TypeError("This Callable type is already parameterized.")
TypeError: This Callable type is already parameterized.

Additional context

Same result when trying with an editable install.

[codeboten]

Thanks for the report! Was able to repro specifically with python 3.5.2, looks fixed in 3.5.3. Will continue digging

[codeboten]

@IurmanJ looks like this is hitting a bug in Python 3.5.2 with the typing library which was refactored here: python/typing@50d2b4d

Is it possible for you to try a newer version of Python?

[IurmanJ]

@codeboten Of course. Actually, that's what I did at the time I opened this issue. Python 3.6 works well, though I did not try 3.5.3 as you reported it was working fine.

[Oberon00]

From my reading, this issue can be closed then. Probably we should add a note to the README that we only support the newest y in each Python 3.x.y.