code: private void executeUpdateKeySpace(Tree statement)
      {
          if (!CliMain.isConnected())
              return;
  
          try
          {
              String keyspaceName = CliCompiler.getKeySpace(statement, thriftClient.describe_keyspaces());
  
              KsDef currentKsDef = getKSMetaData(keyspaceName);
              KsDef updatedKsDef = updateKsDefAttributes(statement, currentKsDef);
  
              String mySchemaVersion = thriftClient.system_update_keyspace(updatedKsDef);
              sessionState.out.println(mySchemaVersion);
              keyspacesMap.remove(keyspaceName);
              getKSMetaData(keyspaceName);
          }
          catch (InvalidRequestException e)
          {
              throw new RuntimeException(e);
          }
          catch (Exception e)
          {
              throw new RuntimeException(e);
          }
      }
docs: Update existing keyspace identified by name
  @param statement - tree represeting statement