Retrieve the annotation types for the given item from the server

        :type item_url: String or Item
        :param item_url: URL of the item, or an Item object

        :rtype: List
        :returns: a List specifying the annotation types

        :raises: APIError if the request was not successful

def get_annotation_types(self, item_url):
        """ Retrieve the annotation types for the given item from the server

        :type item_url: String or Item
        :param item_url: URL of the item, or an Item object

        :rtype: List
        :returns: a List specifying the annotation types

        :raises: APIError if the request was not successful


        """
        req_url = item_url + "/annotations/types"
        resp = self.api_request(req_url)
        return resp['annotation_types']