Make nodes as an agent to run the script inside the stage

I want to make the nodes as one agent to run the scripts. How to add the agent label tag inside the stage by using the nodes?

    {steps
    {script
    {last_started = env.STAGE_NAME
    try{
    def branches = [:]
    def names = FAW_HOSTS.split(',')
    for (int i=0; i<names.size(); ++i) 
    {def nodeName = names[i]; 
    branches[nodeName] = 
    {node(nodeName) 
    {echo "Running patch oci vmscript.."
    def exec = sh(script:"python $source_code_loc/patch_oci_vm.py $WORK_DIR", returnStdout:true).trim()
    echo "$exec"}
    }
    }
    parallel branches
    }
    catch (Exception e)
    {currentBuild.result='FAILURE'
    echo "The current status is ${currentBuild.result}"
    echo "Failed: ${e}"
    error "Run_task_on_multiple_host Stage Failed!"
    }
    }   }
    }