text: 
  from typing import List, Optional
  
  
  # 导入 数据库连接池对象
  from ..databases.relationDatabase.relationDBCli import relation_db_cli
  from ..databases.cacheDatabase.cacheDBCli import cache_db_cli
  
  from ..dataModels.dto import (
      CategoryDTO,
      PageDTO,
  )
  
  from ..dataModels.entity import (
      Article,
      Category,
  
  )
  
  from ..dataModels.vo import (
      ConditionVO,
  
  )
  
  from ..daoOperation import (
      ArticleDao,
      CategoryDao,
  )
  
  
  class CategoryService:
      """
          分类操作逻辑实现
      """
      
      def __init__(self) -> None:
          pass
      
  
      async def listCategories(self) -> PageDTO[CategoryDTO]:
          """
              列出分类信息
          """
          category_dao = CategoryDao()
          async with relation_db_cli.pool.acquire() as conn:
              async with conn.transaction():
                  categorydto_list: List[CategoryDTO] = await category_dao.listCategoryDTO(
                      conn = conn,
                      create_transaction = False
                  )
                  count: Optional[int] = await conn.fetchval(
                      "select count(1) from tb_category;"
                  )
  
          pagedto = PageDTO[CategoryDTO](
              recordList = categorydto_list,
              count = count
          )
          
          return pagedto
  
      
      async def listCategoryBackDTO(
          self,
          conditionVO: ConditionVO ) -> PageDTO[Category]:
          """
              按页列出后台展示的分类信息数据
          """
          # :TODO 这里的count应该代表总数, 所以需要查询再查询一次表总数
          
          raise NotImplementedError("NotImplemented !!!")
  