def METHOD_NAME(self, scale_type="linear"):
    """ Returns a new linear or log scale """
    if scale_type == "linear":
        if self.linear_scale_factory is not None:
            return self.linear_scale_factory()
        else:
            return ScaleSystem(DefaultScale())
    else:
        if self.log_scale_factory is not None:
            return self.log_scale_factory()
        else:
            return ScaleSystem(LogScale())