code: public static void checkIsSetGlobal(final DelegateExecution execution, final String variableName) {
      checkArgument(variableName != null, VARIABLE_NAME_MUST_BE_NOT_NULL);
  
      final Object variable = execution.getVariable(variableName);
      checkState(variable != null, format(CONDITION_VIOLATED + "Global variable '%s' is not set.", execution.getCurrentActivityId(), variableName));
    }
docs: Checks if a global variable is set.
  
  @param execution
  current process execution
  @param variableName
  name of the variable.