code: def issue_types(self):
          
          r_json = self._get_json('issuetype')
          issue_types = [IssueType(
              self._options, self._session, raw_type_json) for raw_type_json in r_json]
          return issue_types
docs: Get a list of issue type Resources from the server.
  
          :rtype: List[IssueType]