code: def make_grid_slot(self, n, m):
          
          def slot_func():
              cont = container.VideoContainerNxM(gpu_handler=self.gpu_handler, 
                                                      filterchain_group=self.filterchain_group, 
                                                      n_dim=n, 
                                                      m_dim=m)
              cont.signals.closing.connect(self.rem_container_slot)
              self.containers.append(cont)
          setattr(self, "grid_%ix%i_slot" % (n, m), slot_func)
docs: Create a n x m video grid, show it and add it to the list of video containers