code: def group(self):
          
          if hasattr(self, 'group_by'):
              group_by = self.group_by
          else:
              group_by = self.default_group_by
              if self.args['group'] is not None:
                  group_by = self.args['group']
  
          self.groups = Grouping(self.logevents, group_by)
          self.groups.move_items(None, 'others')
          self.groups.sort_by_size(group_limit=self.args['group_limit'],
                                   discard_others=self.args['no_others'])
docs: (re-)group all logevents by the given group.