apollo-biz/src/main/java/com/ctrip/framework/apollo/biz/service/NamespaceBranchService.java/NamespaceBranchService/createNamespaceBranch
class NamespaceBranchService:  private Namespace createNamespaceBranch(String appId, String clusterName, String namespaceName, String operator) {
    Namespace childNamespace = new Namespace();
    childNamespace.setAppId(appId);
    childNamespace.setClusterName(clusterName);
    childNamespace.setNamespaceName(namespaceName);
    childNamespace.setDataChangeLastModifiedBy(operator);
    childNamespace.setDataChangeCreatedBy(operator);
    return childNamespace;
  }