在虚拟环境virtualenv中安装ipython时出现Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-GVQWxt/ipython/的错误, python版本2.7

(.env) ...$ pip install ipython
Collecting ipython
  Downloading https://pypi.doubanio.com/packages/fa/50/974211502bd72873728d44c3013fe79875c819c8fb69f778bcfd67bc7d38/ipython-6.2.1.tar.gz (5.1MB)
    100% |████████████████████████████████| 5.1MB 4.0MB/s 
    Complete output from command python setup.py egg_info:
    
    IPython 6.0+ does not support Python 2.6, 2.7, 3.0, 3.1, or 3.2.
    When using Python 2.7, please install IPython 5.x LTS Long Term Support version.
    Beginning with IPython 6.0, Python 3.3 and above is required.
    
    See IPython `README.rst` file for more information:
    
        https://github.com/ipython/ipython/blob/master/README.rst
    
    Python sys.version_info(major=2, minor=7, micro=13, releaselevel='final', serial=0) detected.
    
    
    
    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-GVQWxt/ipython/

解决(原因是新版的ipython只支持python3.4以上版本):

(.env) ...$ pip install ipython==5.5.0