'Construct me.
These parameters are assigned directly as class attributes, see
my L{class documentation<CheckAuthRequest>} for their descriptions.
@type assoc_handle: str
@type signed: L{Message}
@type invalidate_handle: str'

def __init__(self, assoc_handle, signed, invalidate_handle=None):

    self.assoc_handle = assoc_handle
    self.signed = signed
    self.invalidate_handle = invalidate_handle
    self.namespace = OPENID2_NS
