Workaround openmediavault python 3.5 weakref.py error

When you update or install something in openmediavault 4.x and saw theses

Exception ignored in: <function WeakValueDictionary.__init__.<locals>.remove at 0x7fb7d2d82730>
Traceback (most recent call last):
  File "/usr/lib/python3.5/weakref.py", line 117, in remove
TypeError: 'NoneType' object is not callable
Exception ignored in: <function WeakValueDictionary.__init__.<locals>.remove at 0x7fb7d2d82730>
Traceback (most recent call last):
  File "/usr/lib/python3.5/weakref.py", line 117, in remove
TypeError: 'NoneType' object is not callable

You can workaround it with

curl -L https://raw.githubusercontent.com/python/cpython/3.5/Lib/weakref.py > /usr/lib/python3.5/weakref.py