def _find_by_sha1(self, sha1):
        for image_part in self:
            if image_part.sha1 == sha1:
                return image_part
        return None
Add a key to the memcached server, but only if it does not exist. Returns
dataset/ETHPy150Open scanny/python-pptx/pptx/package.py/_ImageParts._find_by_sha1--crossover with--dataset/ETHPy150Open saltstack/salt/salt/modules/memcached.py/add