在Anaconda Prompt中更换成python2.7的环境后jupyter notebook启动不了
在prompt中显示如下信息：

(python26) D:\>jupyter notebook
The Jupyter HTML Notebook.
This launches a Tornado based HTML Notebook Server that serves up an
HTML5/Javascript Notebook client.
Subcommands
-----------
Subcommands are launched as `jupyter-notebook cmd [args]`. For information on
using subcommand 'cmd', do: `jupyter-notebook cmd -h`.
password
    Set a password for the notebook server.
list
    List currently running notebook servers.
Options
-------
Arguments that take values are actually convenience aliases to full
Configurables, whose aliases are listed on the help line. For more information
on full configurables, see '--help-all'.
--script
    DEPRECATED, IGNORED
--pylab
    DISABLED: use %pylab or %matplotlib in the notebook to enable matplotlib.
--debug
    set log level to logging.DEBUG (maximize logging output)
--no-browser
    Don't open the notebook in a browser after startup.
--allow-root
    Allow the notebook to be run from root user.
-y
    Answer yes to any questions instead of prompting.
--no-mathjax
    Disable MathJax
    MathJax is the javascript library Jupyter uses to render math/LaTeX. It is
    very large, so you may want to disable it if you have a slow internet
    connection, or for offline use of the notebook.
    When disabled, equations etc. will appear as their untransformed TeX source.
--no-script
    DEPRECATED, IGNORED
--generate-config
    generate default config file
--certfile=<Unicode> (NotebookApp.certfile)
    Default: u''
    The full path to an SSL/TLS certificate file.
--ip=<Unicode> (NotebookApp.ip)
    Default: 'localhost'
    The IP address the notebook server will listen on.
--pylab=<Unicode> (NotebookApp.pylab)
    Default: 'disabled'
    DISABLED: use %pylab or %matplotlib in the notebook to enable matplotlib.
--log-level=<Enum> (Application.log_level)
    Default: 30
    Choices: (0, 10, 20, 30, 40, 50, 'DEBUG', 'INFO', 'WARN', 'ERROR', 'CRITICAL')
    Set the log level by value or name.
--port-retries=<Integer> (NotebookApp.port_retries)
    Default: 50
    The number of additional ports to try if the specified port is not
    available.
--notebook-dir=<Unicode> (NotebookApp.notebook_dir)
    Default: u''
    The directory to use for notebooks and kernels.
--keyfile=<Unicode> (NotebookApp.keyfile)
    Default: u''
    The full path to a private key file for usage with SSL/TLS.
--client-ca=<Unicode> (NotebookApp.client_ca)
    Default: u''
    The full path to a certificate authority certificate for SSL/TLS client
    authentication.
--config=<Unicode> (JupyterApp.config_file)
    Default: u''
    Full path of a config file.
--port=<Integer> (NotebookApp.port)
    Default: 8888
    The port the notebook server will listen on.
--transport=<CaselessStrEnum> (KernelManager.transport)
    Default: 'tcp'
    Choices: [u'tcp', u'ipc']
--browser=<Unicode> (NotebookApp.browser)
    Default: u''
    Specify what command to use to invoke a web browser when opening the
    notebook. If not specified, the default browser will be determined by the
    `webbrowser` standard library module, which allows setting of the BROWSER
    environment variable to override it.
To see all available configurables, use `--help-all`
Examples
--------
    jupyter notebook                       # start the notebook
    jupyter notebook --certfile=mycert.pem # use SSL/TLS certificate
    jupyter notebook password              # enter a password to protect the server
[C 01:25:44.523 NotebookApp] Bad config encountered during initialization:
[C 01:25:44.523 NotebookApp] Could not decode 'C:\\Users\\\xc5\xed\xcf\xd4\xb9\xa2\\.jupyter' for unicode trait 'config_dir' of a NotebookApp instance.