docs: def move_item(self, item, origin, destination):
          """
          Moves an item from one cluster to anoter cluster.
  
          :param item: the item to be moved.
          :param origin: the originating cluster.
          :param destination: the target cluster.
          """
          if self.equality:
              item_index = 0
              for i, element in enumerate(origin):
                  if self.equality(element, item):
                      item_index = i
                      break
          else:
              item_index = origin.index(item)
  
          destination.append(origin.pop(item_index))