virtual void StartStep() = 0;
  // Destroy the step resource container for a training step.
  virtual void EndStep() = 0;

  // Return the Eager Executor for current thread. Please note that Eager
  // Executor is only used in current TF but not in TFRT.
  virtual EagerExecutor& Executor() = 0;
  // Update the Eager Executor for current thread.
  virtual void SetExecutorForThread(EagerExecutor* executor) = 0;

          items:
          - key: public.crt
            path: public.crt
          - key: private.key
            path: private.key
          - key: public.crt
            path: CAs/public.crt
```

Note that the `secretName` should be same as the secret name created in previous step. Then add the below section under
`spec.containers[].volumeMounts[]`

```yaml
    volumeMounts:
        - name: secret-volume

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.Iterator;
import java.util.NoSuchElementException;
import org.jspecify.annotations.Nullable;

/**
 * Note this class is a copy of {@link com.google.common.collect.AbstractIterator} (for dependency
 * reasons).
 */
@GwtCompatible
abstract class AbstractIterator<T extends @Nullable Object> implements Iterator<T> {

     * accessor types to resolve the value for each successive expression part.
     * Finally, return the result of the last expression part's resolution.</p>
     *
     * <p><b>NOTE:</b> The object-graph navigation actually takes place via the
     * {@link ReflectionValueExtractor} class.</p>
     */
    @Override
    public Object getValue(String expression) {

import org.apache.maven.project.MavenProject;

/**
 * <p>
 * A list of project segments, ordered so that all ProjectSegments from first TaskSegment come before any
 * subsequent TaskSegments.
 * </p>
 * <strong>Note:</strong> This interface is part of work in progress and can be changed or removed without notice.
 *
 * @since 3.0
 */
public class ProjectBuildList implements Iterable<ProjectSegment> {

///

## 宣告模型屬性 { #declare-model-attributes }

接著你可以在模型屬性上使用 `Field`：

{* ../../docs_src/body_fields/tutorial001_an_py310.py hl[11:14] *}

`Field` 的用法與 `Query`、`Path`、`Body` 相同，擁有相同的參數等。

/// note | 技術細節

實際上，你接下來會看到的 `Query`、`Path` 等，會建立共同父類別 `Param` 的子類別物件，而 `Param` 本身是 Pydantic 的 `FieldInfo` 類別的子類別。

而 Pydantic 的 `Field` 也會回傳一個 `FieldInfo` 的實例。

`Body` 也會直接回傳 `FieldInfo` 子類別的物件。稍後你會看到還有其他類別是 `Body` 類別的子類別。

 * {@link MapIteratorCache}, this structure caches values for the two most recently retrieved keys.
 *
 * @author James Sexton
 */
final class MapRetrievalCache<K, V> extends MapIteratorCache<K, V> {
  // See the note about volatile in the superclass.
  private transient volatile @Nullable CacheEntry<K, V> cacheEntry1;
  private transient volatile @Nullable CacheEntry<K, V> cacheEntry2;

  MapRetrievalCache(Map<K, V> backingMap) {

        assertNotNull(inetAddress, "InetAddress should not be null");
    }

    @Test
    @DisplayName("toInetAddress should handle UnknownHostException")
    void testToInetAddressWithException() throws UnknownHostException {
        // Given
        when(mockAddress.toInetAddress()).thenThrow(new UnknownHostException("Host not found"));

        // When & Then

	Class   string // UNIQUE | FULLTEXT | SPATIAL
	Type    string // btree, hash, gist, spgist, gin, and brin
	Where   string
	Comment string
	Option  string        // WITH PARSER parser_name
	Fields  []IndexOption // Note: IndexOption's Field maybe the same
}

type IndexOption struct {
	*Field
	Expression string
	Sort       string // DESC, ASC
	Collate    string
	Length     int
	Priority   int
}

# 標頭參數模型 { #header-parameter-models }

如果你有一組相關的標頭參數，可以建立一個 Pydantic 模型來宣告它們。

這能讓你在多處重複使用該模型，並一次性為所有參數宣告驗證與中繼資料。😎

/// note | 注意

自 FastAPI 版本 `0.115.0` 起支援。🤓

///

## 以 Pydantic 模型宣告標頭參數 { #header-parameters-with-a-pydantic-model }

在 Pydantic 模型中宣告你需要的標頭參數，然後將參數宣告為 `Header`：

{* ../../docs_src/header_param_models/tutorial001_an_py310.py hl[9:14,18] *}

FastAPI 會從請求的標頭為每個欄位擷取資料，並交給你已定義的 Pydantic 模型實例。