code: def _set_interactivity(self, interactivity):
          
          event_default = 'hover'
          if interactivity is None:
              return
          if isinstance(interactivity, (tuple, list)):
              self.interactivity = event_default
              interactive_cols = '\n'.join(
                  '@{0}: ${0}'.format(col) for col in interactivity
              )
          elif isinstance(interactivity, str):
              self.interactivity = event_default
              interactive_cols = '@{0}: ${0}'.format(interactivity)
          elif isinstance(interactivity, dict):
              self.interactivity = interactivity.get('event', event_default)
              self.header = interactivity.get('header')
              interactive_cols = '\n'.join(
                  '@{0}: ${0}'.format(col) for col in interactivity['cols']
              )
          else:
              raise ValueError('`interactivity` must be a str, a list of str, '
                               'or a dict with a `cols` key')
  
          self.styling = '\n'.join([interactive_cols, self.styling])
docs: Adds interactivity syntax to the styling