### Pydantic v1 `regex` en lugar de `pattern`

Antes de la versión 2 de Pydantic y antes de FastAPI 0.100.0, el parámetro se llamaba `regex` en lugar de `pattern`, pero ahora está en desuso.

Todavía podrías ver algo de código que lo usa:

//// tab | Pydantic v1

{* ../../docs_src/query_params_str_validations/tutorial004_regex_an_py310.py hl[11] *}

////

      K key = entry.getKey();
      ImmutableSet.Builder<? extends V> values = (ImmutableSet.Builder<V>) entry.getValue();
      // If orderValuesBy got called at the very end, we may need to do the ImmutableSet to
      // ImmutableSortedSet copy for each of these.
      ImmutableSet<V> set = valueSet(valueComparator, values.build());
      if (!set.isEmpty()) {
        builder.put(key, set);

```Python hl_lines="1  4"
{!> ../../docs_src/python_types/tutorial009b.py!}
```

////

#### Sử dụng `Union` hay `Optional`

If you are using a Python version below 3.10, here's a tip from my very **subjective** point of view:

Nếu bạn đang sử dụng phiên bản Python dưới 3.10, đây là một mẹo từ ý kiến rất "chủ quan" của tôi:

* 🚨 Tránh sử dụng `Optional[SomeType]`

        assertTrue(toStringResult.contains("queryTime=500"));
        assertTrue(toStringResult.contains("partialResults=false"));
    }

    public void test_calculatePageInfo_extremeValues() {
        // Test with very large record count
        QueryResponseList qrList = new QueryResponseList(null, 0, 100, 0) {
            @Override
            public int size() {
                return 100;
            }
        };

is-into-cartoons.com
is-into-games.com
is-leet.com
is-local.org
is-lost.org
is-not-a.dev
is-not-certified.com
is-saved.org
is-slick.com
is-uberleet.com
is-very-bad.org
is-very-evil.org
is-very-good.org
is-very-nice.org
is-very-sweet.org
is-with-theband.com
is.eu.org
is.gov.pl
is.it
isa-geek.com
isa-geek.net
isa-geek.org
isa-hockeynut.com
isa.kagoshima.jp
isa.us

    Castle is great! But it's a large dependency (6.5 MiB) and its security provider feature
    impacts VM-wide behavior.

 *  New: Reduce contention for applications that make a very high number of concurrent requests.
    Previously OkHttp used its connection pool as a lock when making changes to connections and
    calls. With this change each connection is locked independently.

    ```java
        RequestBody.create(null, new byte[0]);
    ```

 * **`CertificatePinner` now supports wildcard hostnames.** As always with
   certificate pinning, you must be very careful to avoid [bricking][brick]
   your app. You'll need to pin both the top-level domain and the `*.` domain
   for full coverage.

    ```java
     client.setCertificatePinner(new CertificatePinner.Builder()

	VSLH V1, V2, V3                 // 10611144
	VSLW V1, V2, V3                 // 10611184
	VSL V1, V2, V3                  // 106111c4
	VSLO V1, V2, V3                 // 1061140c
	VSRB V1, V2, V3                 // 10611204
	VSRH V1, V2, V3                 // 10611244
	VSRW V1, V2, V3                 // 10611284
	VSRD V1, V2, V3                 // 106116c4
	VSR V1, V2, V3                  // 106112c4

		return err
	}
	b := readBuf(buf[:12])
	if b.uint32() != f.CRC32 {
		return ErrChecksum
	}

	// The two sizes that follow here can be either 32 bits or 64 bits
	// but the spec is not very clear on this and different
	// interpretations has been made causing incompatibilities. We
	// already have the sizes from the central directory so we can
	// just ignore these.

	return nil
}

   *       simply switch over to use the JDK implementation wholesale if probable hash flooding is
   *       detected, sacrificing the compactness guarantee in very rare cases in exchange for much
   *       more reliable worst-case behavior.
   *   <li>null, if no entries have yet been added to the map
   * </ul>
   */
  private transient @Nullable Object table;

  /**