When trying to use the variable `BUILD_USER_GROUPS` I get the below error message. Though all the other variables listed in the documentation work. 
hudson.remoting.ProxyException: groovy.lang.MissingPropertyException: No such property: BUILD_USER_GROUPS for class:
 

This is how I am listing them and all of them print correctly except for `BUILD_USER_GROUPS`

wrap([$class: 'BuildUser']) {
echo "${BUILD_USER}"
echo "${BUILD_USER_ID}"
echo "${BUILD_USER_EMAIL}"
echo "${BUILD_USER_GROUPS}"
}