docs: def set_empty_for_all(self, row_column_list):
          """Keep all specified subplots completely empty.
  
          :param row_column_list: a list containing (row, column) tuples to
              specify the subplots, or None to indicate *all* subplots.
          :type row_column_list: list or None
  
          """
          for row, column in row_column_list:
              self.set_empty(row, column)