docs: protected CaseExecutionImpl createCaseExecution(CmmnActivity activity) {
      CaseExecutionImpl child = newCaseExecution();
  
      // set activity to execute
      child.setActivity(activity);
  
      // handle child/parent-relation
      child.setParent(this);
      getCaseExecutionsInternal().add(child);
  
      // set case instance
      child.setCaseInstance(getCaseInstance());
  
      // set case definition
      child.setCaseDefinition(getCaseDefinition());
  
      return child;
    }