'Fetch realms and credentials for the presented request token.
:param uri: The full URI of the token request.
:param http_method: A valid HTTP verb, i.e. GET, POST, PUT, HEAD, etc.
:param body: The request body as a string.
:param headers: The request headers as a dict.
:returns: A tuple of 2 elements.
1. A list of request realms.
2. A dict of credentials which may be useful in creating the
authorization form.'

def get_realms_and_credentials(self, uri, http_method=u'GET', body=None, headers=None):

    request = self._create_request(uri, http_method=http_method, body=body, headers=headers)
    if (not self.request_validator.verify_request_token(request.resource_owner_key, request)):
        raise errors.InvalidClientError()
    realms = self.request_validator.get_realms(request.resource_owner_key, request)
    return (realms, {u'resource_owner_key': request.resource_owner_key})
