https://github.com/Level/level-ttl/blob/f7ead98e6b4631b4782be4fc787e25a61f4eda95/package.json#L20 remove xtend. [They deprecated xtend](https://github.com/Raynos/xtend#deprecated-xtend)
level-ttl/package.json
Line 20 in f7ead98
remove xtend. They deprecated xtend