Local development environment Mac OS X

Continuing the discussion from Getting Started Guide:

I have all the dependencies working and bench is installed.
I’m following https://github.com/frappe/bench#setting-up-erpnext

My current problem is, after entering bench init frappe-bench I get this error message:

Checking connectivity... done.
installing frappe
Compiling .../erpnext/frappe-bench/env/build/gunicorn/gunicorn/workers/_gaiohttp.py ...
  File ".../erpnext/frappe-bench/env/build/gunicorn/gunicorn/workers/_gaiohttp.py", line 64
    yield from self.wsgi.close()
SyntaxError: invalid syntax

After that everything else runs smooth and I’m able to access ERPnext in the browser. But I’m still curious what the error is about and how to solve it.

Seems like an error can you post it on: