<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_institute_trend_graph_url(institute, start, end):
 """ Institute trend graph for machine category. """


    filename = get_institute_trend_graph_filename(institute, start, end)
    urls = {
        'graph_url': urlparse.urljoin(GRAPH_URL, filename + ".png"),
        'data_url': urlparse.urljoin(GRAPH_URL, filename + ".csv"),
    }

    return urls