code: private void executeConsistencyLevelStatement(Tree statement)
      {
          if (!CliMain.isConnected())
              return;
  
          String userSuppliedLevel = statement.getChild(0).getText().toUpperCase();
  
          try
          {
              consistencyLevel = ConsistencyLevel.valueOf(userSuppliedLevel);
          }
          catch (IllegalArgumentException e)
          {
              String elements = "ONE, TWO, THREE, QUORUM, ALL, LOCAL_QUORUM, EACH_QUORUM, ANY";
              sessionState.out.println(String.format("'%s' is invalid. Available: %s", userSuppliedLevel, elements));
              return;
          }
  
          sessionState.out.println(String.format("Consistency level is set to '%s'.", consistencyLevel));
      }
docs: Command: CONSISTENCYLEVEL AS (ONE | QUORUM ...)
  Tree: ^(NODE_CONSISTENCY_LEVEL AS (ONE | QUORUM ...))
  @param statement - tree representing current statement