code: def show_warning(self, index):
          
          try:
              val_size = index.model().sizes[index.row()]
              val_type = index.model().types[index.row()]
          except:
              return False
          if val_type in ['list', 'set', 'tuple', 'dict'] and \
                  int(val_size) > 1e5:
              return True
          else:
              return False
docs: Decide if showing a warning when the user is trying to view
          a big variable associated to a Tablemodel index
  
          This avoids getting the variables' value to know its
          size and type, using instead those already computed by
          the TableModel.
          
          The problem is when a variable is too big, it can take a
          lot of time just to get its value