code: def sensor_names(self):
          
          res = self['/attr/instrument_name']
          if isinstance(res, np.ndarray):
              res = str(res.astype(str))
          res = [x.strip() for x in res.split(',')]
          if len(res) == 1:
              return res[0]
          return res
docs: Return standard sensor or instrument name for the file's data.