code: def _get_scalar_names(self, limit=None):
          
          names = []
          if limit == 'point':
              inpnames = list(self.input_dataset.point_arrays.keys())
          elif limit == 'cell':
              inpnames = list(self.input_dataset.cell_arrays.keys())
          else:
              inpnames = self.input_dataset.scalar_names
          for name in inpnames:
              arr = self.input_dataset.get_scalar(name)
              rng = self.input_dataset.get_data_range(name)
              if arr is not None and arr.size > 0 and (rng[1]-rng[0] > 0.0):
                  names.append(name)
          try:
              self._last_scalars = names[0]
          except IndexError:
              pass
          return names
docs: Only give scalar options that have a varying range