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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def generate_contentinfo_from_folder(self, csvwriter, rel_path, filenames):
 """ Create a topic node row in Content.csv for the folder at `rel_path` and add content node rows for all the files in the `rel_path` folder. """

        LOGGER.debug('IN process_folder ' + str(rel_path) + '     ' + str(filenames))
        from ricecooker.utils.linecook import filter_filenames, filter_thumbnail_files, chan_path_from_rel_path

        # WRITE TOPIC ROW
        topicrow = self.channeldir_node_to_row( rel_path.split(os.path.sep) )
        csvwriter.writerow(topicrow)

        # WRITE CONTENT NODE ROWS
        chan_path = chan_path_from_rel_path(rel_path, self.channeldir)
        filenames_cleaned = filter_filenames(filenames)
        # filenames_cleaned2 = filter_thumbnail_files(chan_path, filenames_cleaned, self)
        for filename in filenames_cleaned:
            path_tuple = rel_path.split(os.path.sep)
            path_tuple.append(filename)
            filerow = self.channeldir_node_to_row(path_tuple)
            csvwriter.writerow(filerow)