def to_python(self, value):
        value = super(SpatialReferenceField, self).to_python(value)
        try:
            return SpatialReference(value)
        except (SRSException, __HOLE__):
            return None
dataset/ETHPy150Open bkg/django-spillway/spillway/forms/fields.py/SpatialReferenceField.to_python