human
Complete the below
@requires_ipython(2.0)
def test_webgl_loading():

    ''''Test if the vispy.ipython extension loads the webGL backend
    on IPython 3.0 and greater.
    Test if it fails to load the webGL backend for IPython versions
    less that 3.0'
    '''
 ... Give me a the Python code you requested?
assistant
#Here is the Python code you requested.
    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)