ImportError:没有名为py31compat的模块

我正在尝试使用

sudo -H pip install --upgrade gensim

但是它给了我这个错误:

but it is giving me this error :

  File "setup.py", line 301, in <module>
    include_package_data=True,
  File "/usr/lib/python2.7/distutils/core.py", line 151, in setup
    dist.run_commands()
  File "/usr/lib/python2.7/distutils/dist.py", line 953, in run_commands
    self.run_command(cmd)
  File "/usr/lib/python2.7/distutils/dist.py", line 972, in run_command
    cmd_obj.run()
  File "/usr/local/lib/python2.7/dist-packages/setuptools/command                      /install.py", line 67, in run
    self.do_egg_install()
  File "/usr/local/lib/python2.7/dist-packages/setuptools/command /install.py", line 98, in do_egg_install
    easy_install = self.distribution.get_command_class('easy_install')
  File "/usr/local/lib/python2.7/dist-packages/setuptools/dist.py", line 576, in get_command_class
    self.cmdclass[command] = cmdclass = ep.load()
  File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 2229, in load
    return self.resolve()
  File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 2235, in resolve
module = __import__(self.module_name, fromlist=['__name__'], level=0)
  File "/usr/local/lib/python2.7/dist-packages/setuptools/command/easy_install.py", line 47, in <module>
from setuptools.sandbox import run_setup
  File "/usr/local/lib/python2.7/dist-packages/setuptools/sandbox.py", line 15, in <module>
    import pkg_resources.py31compat
ImportError: No module named py31compat

请帮助我安装gensim.我用谷歌搜索，但找不到解决方法.

please help me, in installing gensim. i googled it, but i am not able to find the solution.