)

// Checker allows to verify the checksum of a reader.
type Checker struct {
	c io.Closer
	r io.Reader
	h hash.Hash

	want []byte
}

// NewChecker ensures that content with the specified length is read from rc.
// Calling Close on this will close upstream.
func NewChecker(rc io.ReadCloser, h hash.Hash, wantSum []byte, length int64) *Checker {

    def __call__(self, q: str = ""):
        if q:
            return self.fixed_content in q
        return False


checker = FixedContentQueryChecker("bar")


@app.get("/query-checker/")
async def read_query_check(fixed_content_included: bool = Depends(checker)):

## Use the instance as a dependency { #use-the-instance-as-a-dependency }

Then, we could use this `checker` in a `Depends(checker)`, instead of `Depends(FixedContentQueryChecker)`, because the dependency is the instance, `checker`, not the class itself.

And when solving the dependency, **FastAPI** will call this `checker` like:

```Python
checker(q="somequery")
```

## Usar la instance como una dependencia { #use-the-instance-as-a-dependency }

Luego, podríamos usar este `checker` en un `Depends(checker)`, en lugar de `Depends(FixedContentQueryChecker)`, porque la dependencia es la instance, `checker`, no la clase en sí.

Y al resolver la dependencia, **FastAPI** llamará a este `checker` así:

```Python
checker(q="somequery")
```

    "path,expected_status,expected_response",
    [
        (
            "/query-checker/",
            200,
            {"fixed_content_in_query": False},
        ),
        (
            "/query-checker/?q=qwerty",
            200,
            {"fixed_content_in_query": False},
        ),
        (
            "/query-checker/?q=foobar",
            200,
            {"fixed_content_in_query": True},
        ),

              public void close() throws IOException {
                super.close();
                counter[0]--;
              }
            };
          }
        };
    byte[] result = ByteSource.concat(checker, checker, checker).read();
    assertThat(result).hasLength(150);
  }

  private void joinHelper(Integer... spans) throws Exception {
    List<ByteSource> sources = new ArrayList<>();
    int start = 0;

     * This method is not supported in the Fess implementation.
     *
     * @param checker the credential checker to use
     * @throws UnsupportedOperationException always thrown as this method is not supported
     */
    @Override
    protected void checkCredential(final TypicalLoginAssist<String, FessUserBean, FessUser>.CredentialChecker checker) {

          <item index="10" class="java.lang.String" itemvalue="org.checkerframework.checker.nullness.compatqual.NullableDecl" />
          <item index="11" class="java.lang.String" itemvalue="org.checkerframework.checker.nullness.compatqual.NullableType" />
          <item index="12" class="java.lang.String" itemvalue="org.checkerframework.checker.nullness.qual.Nullable" />

## Используем экземпляр как зависимость { #use-the-instance-as-a-dependency }

Затем мы можем использовать этот `checker` в `Depends(checker)` вместо `Depends(FixedContentQueryChecker)`, потому что зависимостью является экземпляр `checker`, а не сам класс.

И при разрешении зависимости **FastAPI** вызовет `checker` примерно так:

```Python
checker(q="somequery")

not use beta APIs, unless you [repackage] them. **If your
code is a library, we strongly recommend using the [Guava Beta Checker] to
ensure that you do not use any `@Beta` APIs!**

[Guava Beta Checker]: https://github.com/google/guava-beta-checker

<!-- References -->