def add_hover_tool(p, rend):
    """ Append hover tool to plot
    parameters
    ----------
    p : bokeh figure
        declares where to append hover tool
    rend : list
        list of renderer to append hover tool
    """
    from bokeh.models import HoverTool
    hover_tool = HoverTool(tooltips=[('Name', '$name'), ('Count',
        '@data_points'), ('Mean', '@average'), ('Deviation', '@deviation')],
        renderers=rend)
    p.tools.append(hover_tool)
