Response time graph for bucketed data

    :param pandas.DataFrame dataframe: dataframe containing all data
    :param str image_name: the output file name
    :param str dir: the output directory
    :return: None

def resp_graph(dataframe, image_name, dir='./'):
    """Response time graph for bucketed data

    :param pandas.DataFrame dataframe: dataframe containing all data
    :param str image_name: the output file name
    :param str dir: the output directory
    :return: None
    """
    fig = pygal.TimeLine(x_title='Elapsed Time In Test (secs)',
                         y_title='Response Time (secs)',
                         x_label_rotation=25,
                         js=('scripts/pygal-tooltip.min.js',))
    fig.add('AVG', [(get_local_time(index), row['mean'] if pd.notnull(row['mean']) else None)
                    for index, row in dataframe.iterrows()])
    fig.add('90%', [(get_local_time(index), row['90%'] if pd.notnull(row['90%']) else None)
                    for index, row in dataframe.iterrows()])
    fig.add('80%', [(get_local_time(index), row['80%'] if pd.notnull(row['80%']) else None)
                    for index, row in dataframe.iterrows()])
    fig.render_to_file(filename=os.path.join(dir, image_name))