def nonsingular(self, vmin, vmax):
    if (vmin == vmax):
        vmin = (vmin - (DAYS_PER_YEAR * 2))
        vmax = (vmax + (DAYS_PER_YEAR * 2))
    return (vmin, vmax)
def nonsingular(self, vmin, vmax):
    if (vmin == vmax):
        vmin = (vmin - (DAYS_PER_YEAR * 2))
        vmax = (vmax + (DAYS_PER_YEAR * 2))
    return (vmin, vmax)