* retrieval operations obtain elements at the head of the queue.
 *
 * <p>This is a classic &quot;bounded buffer&quot;, in which a fixed-sized array holds elements
 * inserted by producers and extracted by consumers. Once created, the capacity cannot be increased.
 * Attempts to {@code put} an element into a full queue will result in the operation blocking;
 * attempts to {@code take} an element from an empty queue will similarly block.
 *

  final void clear() {
    clearCache();
    backingMap.clear();
  }

  @CheckForNull
  V get(Object key) {
    checkNotNull(key);
    V value = getIfCached(key);
    // TODO(b/192579700): Use a ternary once it no longer confuses our nullness checker.
    if (value == null) {
      return getWithoutCaching(key);
    } else {
      return value;
    }
  }

  @CheckForNull
  final V getWithoutCaching(Object key) {

  // indicating the signer failed to issue the certificate.
  //
  // Approved and Denied conditions are mutually exclusive.
  // Approved, Denied, and Failed conditions cannot be removed once added.
  //
  // Only one condition of a given type is allowed.
  optional string type = 1;

  // status of the condition, one of True, False, Unknown.

   * {@link Set}, instead of the {@link Collection} specified in the {@link Multimap} interface.
   *
   * <p>Any duplicates in {@code values} will be stored in the multimap once.
   */
  @CanIgnoreReturnValue
  @Override
  public Set<V> replaceValues(@ParametricNullness K key, Iterable<? extends V> values) {
    return (Set<V>) super.replaceValues(key, values);
  }

  /**

Some requests will have a cached response. When this cached response isn’t fresh, OkHttp can do a _conditional GET_ to download an updated response if it’s newer than what’s cached. This requires headers like `If-Modified-Since` and `If-None-Match` to be added.

## Rewriting Responses

   * {@link Set}, instead of the {@link Collection} specified in the {@link Multimap} interface.
   *
   * <p>Any duplicates in {@code values} will be stored in the multimap once.
   */
  @CanIgnoreReturnValue
  @Override
  public Set<V> replaceValues(@ParametricNullness K key, Iterable<? extends V> values) {
    return (Set<V>) super.replaceValues(key, values);
  }

  /**

    private final String methodName;
    private final String methodDescriptor;

    /**
     * Was upgradedMethods originally, but got renamed to upgradedAccessors and then to replacedAccessors
     * can be removed once base version will be the one that also uses 'replacedAccessors'.
     */
    @SerializedName(value = "replacedAccessors", alternate = {"upgradedAccessors", "upgradedMethods"})

          <defaultValue></defaultValue>
          <identifier>true</identifier>
        </field>
        <field>
          <name>extension</name>
          <version>1.1.0+</version>
          <type>String</type>
          <description>The file extension of the sub-artifact. Each classifier and extension pair may only appear once.</description>

	if w == nil { // when response recorder nil, this is an active request
		hstats.currentS3Requests.Inc(api)
		bh.httpStats[bucket] = hstats
		return
	} // else {
	hstats.currentS3Requests.Dec(api) // decrement this once we have the response recorder.

	hstats.totalS3Requests.Inc(api)
	code := w.StatusCode

	switch {
	case code == 0:
	case code == 499:
		// 499 is a good error, shall be counted as canceled.

そして呼び出すと:

```Python
print(user_dict)
```

以下のようなPythonの`dict`を得ることができます:

```Python
{
    'username': 'john',
    'password': 'secret',
    'email': '******@****.***',
    'full_name': None,
}
```

#### `dict`の展開

`user_dict`のような`dict`を受け取り、それを`**user_dict`を持つ関数（またはクラス）に渡すと、Pythonはそれを「展開」します。これは`user_dict`のキーと値を直接キー・バリューの引数として渡します。

そこで上述の`user_dict`の続きを以下のように書くと:

```Python