@java.lang.Override
  public com.google.protobuf.DurationOrBuilder getRetentionOrBuilder() {
    return retention_ == null ? com.google.protobuf.Duration.getDefaultInstance() : retention_;
  }
<pre>
Optional. How long to keep automated backups before the backups are
deleted. The value should be between 1 day and 365 days. If not specified,
the default value is 35 days.
</pre>

<code>.google.protobuf.Duration retention = 3 [(.google.api.field_behavior) = OPTIONAL];</code>
java-valkey/proto-google-cloud-valkey-v1/src/main/java/com/google/cloud/memorystore/v1/AutomatedBackupConfig.java