Can I use execution.getVariable() inside service task

I cannot use execution.getVariable() inside service task

when i evalute bpmn , I got message

Unable to evaluate script: groovy.lang.MissingPropertyException: No such property: execution for class: Script2

When using connector you have to use connector.getVariable

https://docs.camunda.org/manual/7.7/user-guide/process-engine/scripting/#variables-available-during-script-execution

Thank a lot