MagnificationCurve and lack of methods information

[rpoleski]

>>> import MulensModel as mm
>>> params = mm.ModelParameters({'t_0': 0, 'u_0': 1., 't_E': 9., 's': 1.5, 'q': 0.5, 'alpha': 90.})
>>> mag_curve = mm.MagnificationCurve([0, 1., 10.], params)
>>> mag_curve.get_magnification()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File ".../source/MulensModel/magnificationcurve.py", line 164, in get_magnification
    magnification = self.get_binary_lens_magnification()
  File ".../source/MulensModel/magnificationcurve.py", line 384, in get_binary_lens_magnification
    method = methods[index].lower()
AttributeError: 'NoneType' object has no attribute 'lower'

The message should give some useful information.