Ipython: ipywidgets-7.0.0 not installable with python 2.7?

[daishi]

I am having problems with basic installation

$ python --version
Python 2.7.10
$ pip install ipywidgets
Downloading/unpacking ipywidgets
  Downloading ipywidgets-7.0.0.tar.gz (1.0MB): 1.0MB downloaded
  Running setup.py egg_info for package ipywidgets
    error in ipywidgets setup command: Invalid environment marker: python_version>="3.3"
    Complete output from command python setup.py egg_info:
    error in ipywidgets setup command: Invalid environment marker: python_version>="3.3"

[takluyver]

Update pip and setuptools:

pip install --upgrade setuptools pip