- :param user: user: name, id or None
- :param password: password or None
- :param project: name, id, or None. If None first found project will be used to get an scope token
+ :param credentials: dictionary that contains:
+ username: name, id or None
+ password: password or None
+ project_id: name, id, or None. If None first found project will be used to get an scope token
+ other items are allowed for specific auth backends