Android could not get unknown property for applicationVariants

could not get unknown property for 'applicationVariants' for BuildType xxxx

buildTypes {
    release {
        applicationVariants.all { variant ->
            appendVersionName(variant, defaultConfig)
        }
    }
}

buildTypes {
    release {
       libraryVariants.all { variant ->
            appendVersionName(variant, defaultConfig)
        }
    }
}