'Initialises the Token client
:param auth_url: URL to which the token request is sent
:param disable_ssl_certificate_validation: pass-through to rest client
:param ca_certs: pass-through to rest client
:param trace_requests: pass-through to rest client
:param kwargs: any extra parameter to pass through the rest client.
region, service and auth_provider will be ignored, if passed,
as they are not meaningful for token client'

def __init__(self, auth_url, disable_ssl_certificate_validation=None, ca_certs=None, trace_requests=None, **kwargs):

    dscv = disable_ssl_certificate_validation
    for unwanted_kwargs in ['region', 'service', 'auth_provider']:
        kwargs.pop(unwanted_kwargs, None)
    super(TokenClient, self).__init__(None, None, None, disable_ssl_certificate_validation=dscv, ca_certs=ca_certs, trace_requests=trace_requests, **kwargs)
    if (auth_url is None):
        raise exceptions.IdentityError("Couldn't    determine    auth_url")
    if ('tokens' not in auth_url):
        auth_url = (auth_url.rstrip('/') + '/tokens')
    self.auth_url = auth_url
