@classmethod
def get_session_class(cls, interface_type, resource_class):
    """Return the session class for a given interface type and resource class.

        :type interface_type: constants.InterfaceType
        :type resource_class: str
        :return: Session
        """
    try:
        return cls._session_classes[interface_type, resource_class]
    except KeyError:
        raise ValueError('No class registered for %s, %s' % (interface_type,
            resource_class))
