function insert (self, node, value) {
	  var inserted = node === self.head ?
	    new Node(value, null, node, self) :
	    new Node(value, node, node.next, self);

	  if (inserted.next === null) {
	    self.tail = inserted;
	  }
	  if (inserted.prev === null) {
	    self.head = inserted;
	  }

	  self.length++;

	  return inserted
	}
Check if we should follow the redirect `code`.

@param {Number} code
@return {Boolean}
@api private