docs: def del_records(c_table_cd: str, tables: I2B2Tables) -> int:
          """ Delete all records with c_table_code
  
          :param c_table_cd: key to delete
          :param tables:
          :return: number of records deleted
          """
          conn = tables.ont_connection
          table = tables.schemes
          return conn.execute(table.delete().where(table.c.c_table_cd == c_table_cd)).rowcount