ValueError: Invalid value '"Approved"' for parameter 'status'

Python 2.6.2+ (release26-maint, Jun 19 2009, 15:14:35)
[GCC 4.4.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>import httplib2
>>>the last one ;-)
>>>httplib.debuglevel = 1
>>>import os, string, sys
>>>from launchpadlib.launchpad import Launchpad, EDGE_SERVICE_ROOT
>>>lp_cache_dir = os.path.abspath('./lpbinding/cache')
>>>launchpad = Launchpad.get_token_and_login('moveteams', EDGE_SERVICE_ROOT, lp_cache_dir)
>>>members = launchpad.people["xxxteam"].members
>>>launchpad.people["ubuntu-xx"].addMember(person=members[0], status="Approved")
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Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.6/dist-packages/launchpadlib/resource.py", line 346, in __call__
    **args)
  File "/usr/local/lib/python2.6/dist-packages/wadllib-1.1.1-py2.6.egg/wadllib/application.py", line 591, in build_representation
    media_type, param_values, **kw_param_values)
  File "/usr/local/lib/python2.6/dist-packages/wadllib-1.1.1-py2.6.egg/wadllib/application.py", line 690, in representation
    return definition.bind(param_values, **kw_param_values)
  File "/usr/local/lib/python2.6/dist-packages/wadllib-1.1.1-py2.6.egg/wadllib/application.py", line 801, in bind
    params, param_values, **kw_param_values)
  File "/usr/local/lib/python2.6/dist-packages/wadllib-1.1.1-py2.6.egg/wadllib/application.py", line 169, in validate_param_values
    param_values[name], name, '", "'.join(options)))