def __call__(self):
    try:
        (dmin, dmax) = self.viewlim_to_dt()
    except ValueError:
        return []
    return self.tick_values(dmin, dmax)
def __call__(self):
    try:
        (dmin, dmax) = self.viewlim_to_dt()
    except ValueError:
        return []
    return self.tick_values(dmin, dmax)