NonEmpty isn't a Comonad?

Why is the NonEmpty 开发者_Python百科list from the semigroups package not also an instance of the comonad class?

---

It is. The instance is just defined in the comonad package, and not the semigroups package,

http://hackage.haskell.org/packages/archive/comonad/1.1.0/doc/html/Control-Comonad.html#t:Comonad