def summarize_filetypes(dir_map):
    """
    Given a directory map dataframe, this returns a simple summary of the
    filetypes contained therein and whether or not those are supported or not
    ----------
    dir_map: pandas dictionary with columns path, extension, filetype, support;
            this is the ouput of the map_dirs function
    """
    out_df = dir_map.groupby(["support", "filetype", "extension"])["path"].count()
    return out_df