docs: def type_list(self, index_name):
          '''
          List the types available in an index
          '''
          request = self.session
          url = 'http://%s:%s/%s/_mapping' % (self.host, self.port, index_name)
          response = request.get(url)
          if request.status_code == 200:
              return response[index_name].keys()
          else:
              return response