How to use the graphistry.pygraphistry.PyGraphistry.api_version function in graphistry

::

                    import graphistry
                    graphistry.register('my api key', server='staging', protocol='https')


        **Example: Through environment variable**
                ::
                    export GRAPHISTRY_API_KEY = 'my api key'
                ::
                    import graphistry
                    graphistry.register()
        """
        PyGraphistry.api_key(key)
        PyGraphistry.server(server)
        PyGraphistry.api_version(api)
        PyGraphistry.protocol(protocol)
        PyGraphistry.certificate_validation(certificate_validation)
        PyGraphistry.authenticate()
        PyGraphistry.set_bolt_driver(bolt)

.plot(es)

        """

        if graph is None:
            if self._edges is None:
                util.error('Graph/edges must be specified.')
            g = self._edges
        else:
            g = graph
        n = self._nodes if nodes is None else nodes
        name = name or util.random_string(10)

        self._check_mandatory_bindings(not isinstance(n, type(None)))

        api_version = PyGraphistry.api_version()
        if (api_version == 1):
            dataset = self._plot_dispatch(g, n, name, 'json')
            if skip_upload:
                return dataset
            info = PyGraphistry._etl1(dataset)
        elif (api_version == 2):
            dataset = self._plot_dispatch(g, n, name, 'vgraph')
            if skip_upload:
                return dataset
            info = PyGraphistry._etl2(dataset)

        viz_url = PyGraphistry._viz_url(info, self._url_params)
        cfg_client_protocol_hostname = PyGraphistry._config['client_protocol_hostname']
        full_url = ('%s:%s' % (PyGraphistry._config['protocol'], viz_url)) if cfg_client_protocol_hostname is None else viz_url

        if render == False or (render == None and not self._render):