code: def __find_block_center(self, level_blocks, unhandled_block_indexes):
          
          for i in reversed(range(len(level_blocks))):
              if level_blocks[i].get_density() <= self.__density_threshold:
                  return None
  
              if level_blocks[i].get_cluster() is None:
                  unhandled_block_indexes.remove(i)
                  return level_blocks[i]
  
          return None
docs: !
          @brief Search block that is cluster center for new cluster.
  
          @return (bang_block) Central block for new cluster, if cluster is not found then None value is returned.