anchor.diff:      @init {
           bool if_exists = false;
       }
  -    : K_DROP K_SERVICE_LEVEL (K_IF K_EXISTS { if_exists = true; })? name=serviceLevelOrRoleName
  +    : K_DROP serviceLevel (K_IF K_EXISTS { if_exists = true; })? name=serviceLevelOrRoleName
         { $stmt = std::make_unique<drop_service_level_statement>(name, if_exists); }
       ;
   
  
positive.code: K_SERVICE_LEVELS: S E R V I C E '_' L E V E L S;
  K_ATTACHED: A T T A C H E D;
  K_FOR: F O R;
  
  K_SCYLLA_TIMEUUID_LIST_INDEX: S C Y L L A '_' T I M E U U I D '_' L I S T '_' I N D E X;
  K_SCYLLA_COUNTER_SHARD_LIST: S C Y L L A '_' C O U N T E R '_' S H A R D '_' L I S T; 
  
negative.code:         | K_FOR
          | K_GROUP
          | K_TIMEOUT
          | K_SERVICE
          | K_LEVEL
          | K_LEVELS
          ) { $str = $k.text; }
      ;
  
  