code: def dispatch(self, receiver):
          ''' Dispatch handling of this event to a receiver.
  
          This method will invoke ``receiver._column_data_changed`` if it exists.
  
          '''
          super(ColumnDataChangedEvent, self).dispatch(receiver)
          if hasattr(receiver, '_column_data_changed'):
              receiver._column_data_changed(selff dispatch(self, receiver):
          ''' Dispatch handling of this event to a receiver.
  
          This method will invoke ``receiver._column_data_changed`` if it exists.
  
          '''
          super(ColumnDataChangedEvent, self).dispatch(receiver)
          if hasattr(receiver, '_column_data_changed'):
              receiver._column_data_changed(self)
docs: Dispatch handling of this event to a receiver.
  
          This method will invoke ``receiver._column_data_changed`` if it exists.