def chunk(self):
        if not self.iter:
            return b""
        try:
            return six.next(self.iter)
        except __HOLE__:
            self.iter = None
            return b""
dataset/ETHPy150Open RoseOu/flasky/venv/lib/python2.7/site-packages/gunicorn/http/unreader.py/IterUnreader.chunk