from typing import Annotated, Union

from fastapi import Body, FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: Union[float, None] = None


class User(BaseModel):
    username: str
    full_name: Union[str, None] = None


@app.put("/items/{item_id}")
async def update_item(
    *,
    item_id: int,

 * which implementation should be injected when multiple candidates exist.
 * The value represents a unique identifier for the dependency.
 * <p>
 * Example usage:
 * <pre>
 * {@literal @}Inject
 * {@literal @}Named("mysql")
 * private Repository mysqlRepository;
 * </pre>
 *
 * @see Inject
 * @see Qualifier
 * @since 4.0.0
 */
@Qualifier
@Retention(RUNTIME)
@Documented
public @interface Named {
    /**

 * throughout the Maven build process.
 * <p>
 * Example usage:
 * <pre>
 * public class CustomLanguageProvider implements LanguageProvider {
 *     public Collection&lt;Language&gt; provides() {
 *         return Collections.singleton(language("kotlin"));
 *     }
 * }
 * </pre>
 *
 * @see org.apache.maven.api.Language
 * @see org.apache.maven.api.spi.ExtensibleEnumProvider
 * @since 4.0.0

```Python hl_lines="4  9-12  25-27"
from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Union[bool, None] = None


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):

So, if you send a request to that *path operation* for the item with ID `foo`, the response (not including default values) will be:

```JSON
{
    "name": "Foo",
    "price": 50.2
}
```

/// info

You can also use:

* `response_model_exclude_defaults=True`
* `response_model_exclude_none=True`

Então, se você enviar uma solicitação para essa *operação de rota* para o item com ID `foo`, a resposta (sem incluir valores padrão) será:

```JSON
{
    "name": "Foo",
    "price": 50.2
}
```

/// info | Informação

No Pydantic v1, o método era chamado `.dict()`, ele foi descontinuado (mas ainda suportado) no Pydantic v2 e renomeado para `.model_dump()`.

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  public void testIsNull_serialization() {
    Predicate<String> pre = Predicates.isNull();
    Predicate<String> post = SerializableTester.reserializeAndAssert(pre);
    assertEquals(pre.apply("foo"), post.apply("foo"));
    assertEquals(pre.apply(null), post.apply(null));
  }

  public void testNotNull_apply() {

        repositoryRequest.setLocalRepository(getLocalRepository());
        repositoryRequest.setRemoteRepositories(getPluginArtifactRepositories());

        // prime realm cache
        MavenSession session = createMavenSession(getProject("project-contributing-system-scope-plugin-dep"));
        MavenProject project = session.getCurrentProject();

 * Instances of {@link BeanDesc} are obtained from {@link BeanDescFactory}.
 * </p>
 *
 * <pre>
 * BeanDesc beanDesc = BeanDescFactory.getBeanDesc(Foo.class);
 * </pre>
 * <p>
 * From the obtained {@link BeanDesc}, you can retrieve metadata of the properties, fields, constructors, and methods of the target JavaBeans.
 * </p>
 *
 * <pre>
 * for (PropertyDesc propertyDesc : beanDesc.getPropertyDescs()) {

/**
 * This class generates {@link BeanDesc}.
 * <p>
 * It returns a {@link BeanDesc} that handles the metadata of the specified JavaBeans.
 * </p>
 *
 * <pre>
 * BeanDesc beanDesc = BeanDescFactory.getBeanDesc(Foo.class);
 * </pre>
 * <p>
 * {@link BeanDesc} is cached. To clear the cache, call {@link DisposableUtil#dispose()}.
 * </p>
 *
 * @author higa
 * @see BeanDesc
 * @see DisposableUtil
 */