It does, but I can't pass `git_tree` to `-[GTTree objectWithObj:inRepository:]`, because it expects `git_object`

    error: incompatible pointer types sending 'git_tree *' (aka 'struct git_tree *') to parameter of type 'git_object *' (aka 'struct git_object *') [-Werror,-Wincompatible-pointer-types]
        return [GTTree objectWithObj:tree inRepository:repository];