human
I wrote the below code

    import IPython
    from distutils.version import LooseVersion
    from IPython.testing.globalipapp import get_ipython
    ipy = get_ipython()
    ipy.run_cell('from    vispy    import    app')
    if (LooseVersion(IPython.__version__) >= LooseVersion('3.0.0')):
        ipy.run_cell('%load_ext    vispy.ipython')
        ipy.run_cell('backend_name    =    app.use_app().backend_name')
        assert_equal(ipy.user_ns['backend_name'], 'ipynb_webgl')
    else:
        ipy.run_cell('%load_ext    vispy.ipython')
        ipy.run_cell('backend_name    =    app.use_app().backend_name')
        def invalid_backend_access(ipy):
            ipy.user_ns['backend_name']
        assert_raises(KeyError, invalid_backend_access, ipy)

What's a good function header?
assistant
#Here's a good function header.

@requires_ipython(2.0)
def test_webgl_loading():