code: def get_labels(self, depth=None):
          
          labels = libCopy.deepcopy(self.labels)
          if depth is None or depth > 0:
              for element in self.elements:
                  if isinstance(element, CellReference):
                      labels.extend(
                          element.get_labels(None if depth is None else depth -
                                             1))
                  elif isinstance(element, CellArray):
                      labels.extend(
                          element.get_labels(None if depth is None else depth -
                                             1))
          return labels
docs: Returns a list with a copy of the labels in this cell.
  
          Parameters
          ----------
          depth : integer or ``None``
              If not ``None``, defines from how many reference levels to
              retrieve labels from.
  
          Returns
          -------
          out : list of ``Label``
              List containing the labels in this cell and its references.