docs: def count_row(engine, table):
      """
      Return number of rows in a table.
  
      Example::
  
          >>> count_row(engine, table_user)
          3
  
      **中文文档**
  
      返回一个表中的行数。
      """
      return engine.execute(select([func.count()]).select_from(table)).fetchone()[0]