public Builder clearAnnouncement() {
            announcement_ = getDefaultInstance().getAnnouncement();
            bitField0_ &= ~0x00000040;
            onChanged();
            return this;
        }
<code>optional string announcement = 7;</code>

@return This builder for chaining.
turms-server-common/src/main/java/im/turms/server/common/access/client/dto/model/group/Group.java