':param str account_sid: The account sid to which this token is granted access.
:param str auth_token: The secret key used to sign the token. Note, this auth token is not
visible to the user of the token.
:param int nbf: Time in secs from epic before which this token is considered invalid.
:param int ttl: the amount of time in seconds from generation that this token is valid for.
:param kwargs:
:returns: A new CapabilityToken with zero permissions'

def __init__(self, account_sid, auth_token, nbf=None, ttl=3600, valid_until=None, **kwargs):

    super(ClientCapabilityToken, self).__init__(algorithm='HS256', secret_key=auth_token, issuer=account_sid, nbf=nbf, ttl=ttl, valid_until=None)
    self.account_sid = account_sid
    self.auth_token = auth_token
    self.client_name = None
    self.capabilities = {}
    if ('allow_client_outgoing' in kwargs):
        self.allow_client_outgoing(**kwargs['allow_client_outgoing'])
    if ('allow_client_incoming' in kwargs):
        self.allow_client_incoming(**kwargs['allow_client_incoming'])
    if ('allow_event_stream' in kwargs):
        self.allow_event_stream(**kwargs['allow_event_stream'])
