如何在Jenkinsfile中引入时间戳变量

pipeline {
    agent any

    environment {

       _version = sh(script: "echo `date '+%Y%m%d%H%M%S'`", returnStdout: true).trim()
    }

    stages {
        stage ("test") {
            steps {
                echo "${_version}"
            }
        }
    }
}

def createVersion() {
    return new Date().format('yyyyMMddHHmmss') + "_${env.BUILD_ID}"
}

pipeline {
    agent any
    environment {
        _version = createVersion()
    }
    stages {
        stage ("test") {
            steps {
                echo "${_version}"
            }
        }
    }
}

def getTimeStamp(){
    return sh (script: "date +'%Y%m%d%H%M%S%N' | sed 's/[0-9][0-9][0-9][0-9][0-9][0-9]\$//g'", returnStdout: true);
}

pipeline {
    agent any

    environment {

       _version =  getTimeStamp()
    }

    stages {
        stage ("test") {
            steps {
                echo "${_version}"
            }
        }
    }
}

参考：
https://community.jenkins-zh.cn/t/jenkinsfile/176