How to use the feedgenerator.Enclosure function in feedgenerator

tu = e.get('updated_parsed')
            if tu:
                metadata['updateddate'] = datetime.datetime(*tu[:5] +
                                                            (min(tu[5], 59),))

            metadata['comments'] = e.get('comments')
            metadata['unique_id'] = e.get('id')
            metadata['item_copyright'] = e.get('license')

            if 'tags' in e:
                taglist = [tag.get('term') for tag in e['tags']]
                metadata['categories'] = taglist
            if 'enclosures' in e:
                enclist = []
                for enc in e['enclosures']:
                    enclist.append(feedgenerator.Enclosure(enc.href, enc.length,
                                                           enc.type))
                metadata['enclosures'] = enclist
                if len(enclist) > 0:
                    # The current standalone version of feedgenerator does not
                    # handle 'enclosures' only a single 'enclosure'
                    metadata['enclosure'] = enclist[0]

            mixed_entries.append(metadata)
        return mixed_entries