incompatibility sphinx - urllib3

[frédéric dubois]

Dear all,

After the last update of my ports it appears a problem with sphinx while 
generating some documentation of my code.
As far I understand the problem is due to the update of urllib3.
Any idea on how to fix this problem ?

Regards

%<--
sphinx build log message

   File "/opt/local/bin/sphinx-build", line 6, in <module>
     from pkg_resources import load_entry_point
   File 
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pkg_resources/__init__.py", line 3038, in <module>
     @_call_aside
   File 
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pkg_resources/__init__.py", line 3022, in _call_aside
     f(*args, **kwargs)
   File 
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pkg_resources/__init__.py", line 3051, in _initialize_master_working_set
     working_set = WorkingSet._build_master()
   File 
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pkg_resources/__init__.py", line 659, in _build_master
     return cls._build_from_requirements(__requires__)
   File 
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pkg_resources/__init__.py", line 672, in _build_from_requirements
     dists = ws.resolve(reqs, Environment())
   File 
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pkg_resources/__init__.py", line 857, in resolve
     raise DistributionNotFound(req, requirers)
pkg_resources.DistributionNotFound: The 'urllib3<1.22,>=1.21.1' 
distribution was not found and is required by requests

%<--

during last update

--->  Computing dependencies for py27-urllib3
--->  Fetching archive for py27-urllib3
--->  Attempting to fetch py27-urllib3-1.22_0.darwin_15.x86_64.tbz2 from 
https://packages.macports.org/py27-urllib3
--->  Attempting to fetch 
py27-urllib3-1.22_0.darwin_15.x86_64.tbz2.rmd160 from 
https://packages.macports.org/py27-urllib3
--->  Installing py27-urllib3 @1.22_0
--->  Cleaning py27-urllib3
--->  Computing dependencies for py27-urllib3
--->  Deactivating py27-urllib3 @1.21.1_0
--->  Cleaning py27-urllib3
--->  Activating py27-urllib3 @1.22_0
--->  Cleaning py27-urllib3

%<--



-- 
Frédéric Dubois, PhD, Eng.
Laboratoire de Mécanique et Génie Civil - CNRS/UM2
http://www.lmgc.univ-montp2.fr/~dubois
Tel: (33/0) 467144984
Mobile: (33/0) 635490843