'Check that angles are between -90 and 90 degrees.
If not given, the check is done on the object itself'

def _validate_angles(self, angles=None):

    if (angles is None):
        angles = self
    lower = u.degree.to(angles.unit, (-90.0))
    upper = u.degree.to(angles.unit, 90.0)
    if (np.any((angles.value < lower)) or np.any((angles.value > upper))):
        raise ValueError(u'Latitude    angle(s)    must    be    within    -90    deg    <=    angle    <=    90    deg,    got    {0}'.format(angles.to(u.degree)))
