#!/usr/bin/python3

import ox

url = 'https://pandora/api/'
username = 'fixme'
password = 'fixme'

listname = 'a:foobar'
group = 'example'

api = ox.API(url)
api.signin(username=username, password=password)
for item in api.find({
    'query': {
        'conditions': [{
            'key': 'list',
            'value': listname,
            'operator': '=='
        }]
    },
    'keys': ['id'],
    'range': [0, 5000]
})['data']['items']:
    api.edit({
        'id': item['id'],
        'groups': [group]
    })