def METHOD_NAME(cnt_viewmodel):
    """
    Open the webpage at container ip and host port we exposed when we ran this container.
    Raise error if container not running and prompt user to choose host port if multiple
    host ports exposed under this container.
    :param cnt_viewmodel: ContainerViewModel: contains view info about container
    :return: None
    """
    if not cnt_viewmodel.is_running():
        raise RuntimeError(strings['local.open.nocontainer'])
    # Get container id, exposed host port pairs
    cid_hostports = cnt_viewmodel.get_cid_hostport_pairs()
    num_exposed_hostports = cnt_viewmodel.num_exposed_hostports()
    if num_exposed_hostports == 1:
        _, host_port = cid_hostports[0]
    elif num_exposed_hostports > 1:
        io.echo()
        io.echo('Select a container applcation to open')
        io.echo()
        disp = ['Container {}, host port {}'.format(cid, p) for cid, p in cid_hostports]
        ind = utils.prompt_for_index_in_list(disp)
        _, host_port = cid_hostports[ind]
    else:
        raise RuntimeError(strings['local.open.noexposedport'])
    url = '{}:{}'.format(cnt_viewmodel.ip, host_port)
    commonops.open_webpage_in_browser(url)