code: def get_dataset(self, name, multi_instance=0):
          
          return [elem for elem in self._data_list
                  if elem.name == name and elem.multi_id == multi_instance][0]
docs: get a specific dataset.
  
          example:
          try:
              gyro_data = ulog.get_dataset('sensor_gyro')
          except (KeyError, IndexError, ValueError) as error:
              print(type(error), "(sensor_gyro):", error)
  
          :param name: name of the dataset
          :param multi_instance: the multi_id, defaults to the first
          :raises KeyError, IndexError, ValueError: if name or instance not found