example to show that a subsequent upload of an ia-wrapper Item will show metadata from a previous Item.

clobberempty.py

#! /usr/bin/env python
# -*- coding: utf-8 -*-
import datetime
import internetarchive as ia
import os
from tempfile import NamedTemporaryFile


ACCESS_KEY = os.environ.get('IAS3_ACCESS_KEY') 
SECRET_KEY = os.environ.get('IAS3_SECRET_KEY')

now = datetime.datetime.utcnow().strftime('%Y_%m_%d_%H%M%S')

item = ia.Item('test_upload_iawrapper_first_%s' % now)
item2 = ia.Item('test_upload_iawrapper_second_%s' % now)

def upload(item, metadata):
    with NamedTemporaryFile() as fh:
        fh.write('testing archive_uploader')
        item.upload(fh.name,
            metadata=metadata,
            access_key=ACCESS_KEY,
            secret_key=SECRET_KEY
        )

upload(item,
       metadata={
           'collection': 'test_collection',
           'description': 'not an empty description',
        })

upload(item2,
       metadata={
           'collection': 'test_collection',
           'description': '',
        })

print 'visit https://archive.org/details/{}'.format(item.identifier)
print 'visit https://archive.org/details/{}'.format(item2.identifier)

I found this also happens if item2's metadata doesn't have a description item.

btw, adding header={} after L23 is a workaround