code: function inTree(root, oid) {
          var i;
          if (oid.length <= root.length) {
              return false;
          }
          for (i = 0; i < root.length; i++) {
              if (oid[i] !== root[i]) {
                  return false;
              }
          }
          return true;
      }
docs: Helper to check whether `oid` in inside the tree rooted at `root` or not.