code: def set_used_labels(self, labels):
          
          mask = np.zeros(self.cl_.size, dtype=bool)
          for l in labels:
              mask = np.logical_or(mask, self.cl_ == l)
          self.trial_mask_ = mask
          return self
docs: Specify which trials to use in subsequent analysis steps.
  
          This function masks trials based on their class labels.
  
          Parameters
          ----------
          labels : list of class labels
              Marks all trials that have a label that is in the `labels` list for further processing.
  
          Returns
          -------
          self : Workspace
              The Workspace object.