private com.google.protobuf.MapField<java.lang.String, im.turms.server.common.access.client.dto.model.common.Value> internalGetUserDefinedAttributes() {
        if (userDefinedAttributes_ == null) {
            return com.google.protobuf.MapField
                    .emptyMapField(UserDefinedAttributesDefaultEntryHolder.defaultEntry);
        }
        return userDefinedAttributes_;
    }
<code>optional int64 successor_id = 9;</code>

@return The successorId.
turms-server-common/src/main/java/im/turms/server/common/access/client/dto/request/group/UpdateGroupRequest.java