def _first_ifd(self):
        return self.s2n(4, 4)
Debug a test script.  `src` is the script, as a string.
dataset/ETHPy150Open ianare/exif-py/exifread/classes.py/ExifHeader._first_ifd--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.2/django/test/_doctest.py/debug_script