// allows depMgmt to always override transitive dependencies, while
        // explicit child override depMgmt (viz. depMgmt should only
        // provide defaults to children, but should override transitives).
        // We can do this by calling isChildOfRootNode on the current node.
        if ((artifact.getVersion() != null)

    private long encryptionStartTime = System.currentTimeMillis();

    // Configurable key rotation limits with defaults
    private volatile long keyRotationBytesLimit = 1L << 30; // Default: 1GB
    private volatile long keyRotationTimeLimit = 24 * 60 * 60 * 1000L; // Default: 24 hours

    // Rotation metrics
    private final AtomicLong totalKeyRotations = new AtomicLong(0);

     * for its target model. The default returns 4000 for backward compatibility.
     *
     * @return the maximum history characters
     */
    protected int getHistoryMaxChars() {
        return 4000;
    }

    /**
     * Gets the maximum number of history messages for intent detection.

    </ul>
    ]]>
  </description>
  <defaults>
    <default>
      <key>package</key>
      <value>org.apache.maven.model</value>
    </default>
  </defaults>
  <classes>
    <class rootElement="true" xml.tagName="project">
      <name>Model</name>
      <superClass>ModelBase</superClass>
      <description>

     * list, the default property list, and its defaults, recursively, are then checked. The method returns the default
     * value argument if the property is not found.
     *
     * @param key the property key.
     * @param defaultValue a default value.
     * @return The property value of the default value
     */
    public String getProperty(String key, String defaultValue) {

     * list, the default property list, and its defaults, recursively, are then checked. The method returns the default
     * value argument if the property is not found.
     *
     * @param key the property key.
     * @param defaultValue a default value.
     * @return The property value of the default value
     */
    public String getProperty(String key, String defaultValue) {

        } else {
            // fall back to default log level specified in conf
            // see https://issues.apache.org/jira/browse/MNG-2570 and https://github.com/apache/maven/issues/11199
            context.loggerLevel = Slf4jConfiguration.Level.INFO; // default for display purposes
        }
    }

* Pod priority and preemption is now enabled by default. Even if you don't plan to use this feature, you might need to take some action immediately after upgrading. In multi-tenant clusters where not all users are trusted, you are advised to create appropriate quotas for two default priority classes, system-cluster-critical and system-node-critical, which are added to clusters by default. `ResourceQuota` should be created to limit users from creating Pods at these priorities...

所以：

```Python
q: str | None = Query(default=None)
```

...会让参数变成可选，默认值为 `None`，等同于：

```Python
q: str | None = None
```

但使用 `Query` 的版本会显式把它声明为一个查询参数。

然后，我们可以向 `Query` 传入更多参数。本例中是适用于字符串的 `max_length` 参数：

```Python
q: str | None = Query(default=None, max_length=50)
```

  // appended later), but should include any information specific to this custom
  // device which would be useful for debugging.
  //
  // Optional. If null, defaults to resolving the TFE_TensorHandle into a
  // TF_Tensor and summarizing that.
  TF_Buffer* (*summarize)(void* data, TF_Status* status) = nullptr;
} TFE_CustomDeviceTensorHandle;