code: def update_extra_selections(self):
          
          extra_selections = []
  
          for key, extra in list(self.extra_selections_dict.items()):
              extra_selections.extend(extra)
          self.decorations.add(extra_selections)
docs: Add extra selections to DecorationsManager.
  
          TODO: This method could be remove it and decorations could be
          added/removed in set_extra_selections/clear_extra_selections.