_NamespacePath object has no attribute sort (31.0.0)

When pip installing a package that shares a namespace it fails out on 31.0.0 but installs fine on 28.8.0

    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/usr/lib/python3.5/site-packages/setuptools/__init__.py", line 10, in <module>
        from setuptools.extern.six.moves import filter, filterfalse, map
      File "/usr/lib/python3.5/site-packages/setuptools/extern/__init__.py", line 1, in <module>
        from pkg_resources.extern import VendorImporter
      File "/usr/lib/python3.5/site-packages/pkg_resources/__init__.py", line 3015, in <module>
        @_call_aside
      File "/usr/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2999, in _call_aside
        f(*args, **kwargs)
      File "/usr/lib/python3.5/site-packages/pkg_resources/__init__.py", line 3043, in _initialize_master_working_set
        for dist in working_set
      File "/usr/lib/python3.5/site-packages/pkg_resources/__init__.py", line 3043, in <genexpr>
        for dist in working_set
      File "/usr/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2573, in activate
        declare_namespace(pkg)
      File "/usr/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2147, in declare_namespace
        _handle_ns(packageName, path_item)
      File "/usr/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2087, in _handle_ns
        _rebuild_mod_path(path, packageName, module)
      File "/usr/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2116, in _rebuild_mod_path
        orig_path.sort(key=position_in_sys_path)
    AttributeError: '_NamespacePath' object has no attribute 'sort'

[SeungKil-Paek]

I modified the function _rebuild_mod_path of the file(.../site-packages/pip/_vendor/pkg_resources/__init__.py), which worked:

orig_path_t = list(orig_path) # added
#orig_path.sort(key=position_in_sys_path) # commented
orig_path_t.sort(key=position_in_sys_path) # added
#module.__path__[:] = [_normalize_cached(p) for p in orig_path] # commented
module.__path__[:] = [_normalize_cached(p) for p in orig_path_t] # added

[chexex]

hmm… how might one follow @frankyaorenjie 's solution just above if attempting to use pip to upgrade (or uninstall) setuptools also throws that error?

This helped me with the issue

easy_install pip
easy_install setuptools