oem_list = None
  if options.customer_filter:
    # cache this list so we're not fetching something huge
    # everytime in the loop
     oem = lp.people['canonical']
     oem_list = list(oem.members_details)
...

    if options.customer_filter is False:
      tags = update_tags(tags, options.update_from, options.update_to)
      bug_updated = True
    else:
      # Everyone outside of this set should be an OEM customer
      assignee = task.assignee_link
      print "id %s assigned to %s" % (bug.id, assignee)
      if assignee is None or assignee not in oem_list:
        tags = update_tags(tags, options.update_from, options.update_to)
        bug_updated = True
      else:
        bug_updated = False

=== output ===

<11:40:14>tmp$ ./manz_lp_retag.py --from-tag waiting-for-oem --to-tag oem-verification-pending --not-canonical --dry-run --state 'Incomplete (with response)' --state 'Incomplete (without response)' --state 'Incomplete'
id 720891 assigned to None
id:720891, owner:https://api.launchpad.net/1.0/~gilbert-hyatt, state:Incomplete, old_tags:[u'waiting-for-oem'], new_tags:['oem-verification-pending']
id 971999 assigned to https://api.launchpad.net/1.0/~binh-t-vu
ERROR: 'unicode' object has no attribute 'self_link'