LIGOTimeGPS(None) causes segmentation fault

The following causes a segmentation fault on python2.7 and python3.6 on macOS (using macports py27-lal @6.18.0_3):

>>> from lal import LIGOTimeGPS
>>> LIGOTimeGPS(None)

I realise that this is clearly a nonesense operation, but it would be nice for this to raise a TypeError rather than crashing python.