python3 安装demjson 报错 use_2to3 is invalid

ooking in indexes: https://pypi.douban.com/simple

Collecting demjson==2.2.4

  Downloading https://pypi.doubanio.com/pack ... ar.gz (131 kB)

     |████████████████████████████████| 131 kB 985 kB/s

    ERROR: Command errored out with exit status 1:

     command: /root/miniconda3/envs/py37/bin/python -c 'import io, os, sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-pj0ajcpl/demjson_86a1bab6643c4ed7a7b0c6bb6d3a43a2/setup.py'"'"'; __file__='"'"'/tmp/pip-install-pj0ajcpl/demjson_86a1bab6643c4ed7a7b0c6bb6d3a43a2/setup.py'"'"';f = getattr(tokenize, '"'"'open'"'"', open)(__file__) if os.path.exists(__file__) else io.StringIO('"'"'from setuptools import setup; setup()'"'"');code = f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/pip-pip-egg-info-7ve4tu87

         cwd: /tmp/pip-install-pj0ajcpl/demjson_86a1bab6643c4ed7a7b0c6bb6d3a43a2/

    Complete output (3 lines):

    /root/miniconda3/envs/py37/lib/python3.7/site-packages/setuptools/dist.py:760: UserWarning: Usage of dash-separated 'index-url' will not be supported in future versions. Please use the underscore name 'index_url' instead

      % (opt, underscore_opt)

    error in demjson setup command: use_2to3 is invalid.