pip install gapic-google-cloud-pubsub-v1 failed

Collecting gapic-google-cloud-pubsub-v1<0.16dev,>=0.15.0 (from google-cloud-pubsub)
  Downloading gapic-google-cloud-pubsub-v1-0.15.3.tar.gz
    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/home/naresh/Downloads/2017/march/android-vts/venv/lib/python3.5/site-packages/setuptools/__init__.py", line 12, in <module>
        import setuptools.version
      File "/home/naresh/Downloads/2017/march/android-vts/venv/lib/python3.5/site-packages/setuptools/version.py", line 1, in <module>
        import pkg_resources
      File "/home/naresh/Downloads/2017/march/android-vts/venv/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2927, in <module>
        @_call_aside
      File "/home/naresh/Downloads/2017/march/android-vts/venv/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2913, in _call_aside
        f(*args, **kwargs)
      File "/home/naresh/Downloads/2017/march/android-vts/venv/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2952, in _initialize_master_working_set
        add_activation_listener(lambda dist: dist.activate())
      File "/home/naresh/Downloads/2017/march/android-vts/venv/lib/python3.5/site-packages/pkg_resources/__init__.py", line 956, in subscribe
        callback(dist)
      File "/home/naresh/Downloads/2017/march/android-vts/venv/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2952, in <lambda>
        add_activation_listener(lambda dist: dist.activate())
      File "/home/naresh/Downloads/2017/march/android-vts/venv/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2515, in activate
        declare_namespace(pkg)
      File "/home/naresh/Downloads/2017/march/android-vts/venv/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2097, in declare_namespace
        _handle_ns(packageName, path_item)
      File "/home/naresh/Downloads/2017/march/android-vts/venv/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2047, in _handle_ns
        _rebuild_mod_path(path, packageName, module)
      File "/home/naresh/Downloads/2017/march/android-vts/venv/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2066, in _rebuild_mod_path
        orig_path.sort(key=position_in_sys_path)
    AttributeError: '_NamespacePath' object has no attribute 'sort'

    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-kmc33b0l/gapic-google-cloud-pubsub-v1/