def _bz4_compat_transform(bug, event, objdict, obj):
    """Modify the bug, event and obj dicts for a message to look more
    like a Bugzilla 4-era message's dicts did. Returns nothing as it
    modifies the dicts in place.
    """
    if bug.get('assigned_to', {}).get('login'):
        bug['assigned_to'] = bug['assigned_to']['login']
    if bug.get('component', {}).get('name'):
        bug['component'] = bug['component']['name']
    if bug.get('product', {}).get('name'):
        bug['product'] = bug['product']['name']
    bug['cc'] = bug.get('cc', [])
    if bug.get('reporter', {}).get('login'):
        bug['creator'] = bug['reporter']['login']
    if bug.get('operating_system'):
        bug['op_sys'] = bug['operating_system']
    if not bug.get('weburl'):
        bug['weburl'] = 'https://bugzilla.redhat.com/show_bug.cgi?id=%s' % bug[
            'id']
    event['who'] = event['user']['login']
    event['changes'] = event.get('changes', [])
    for change in event['changes']:
        change['field_name'] = change['field']
    if obj == 'comment':
        objdict[obj]['author'] = event.get('user', {}).get('login', '')
