}
    }
  }

  /**
   * Test for 2-bit characteristics. A characteristic is a delta in the input which is repeated in
   * the output. For example, if f() is a block cipher and c is a characteristic, then f(x^c) =
   * f(x)^c with greater than expected probability. The test for funneling is merely a test for
   * 1-bit characteristics.
   *

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/// note

FastAPI will know that the value of `q` is not required because of the default value `= None`.

The `Union` in `Union[str, None]` will allow your editor to give you better support and detect errors.

///

## Additional validation

We are going to enforce that even though `q` is optional, whenever it is provided, **its length doesn't exceed 50 characters**.

### Import `Query` and `Annotated`

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    FastAPI 框架，高性能，易于学习，高效编码，生产可用
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gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
gotest.tools/v3 v3.0.3 h1:4AuOwCGf4lLR9u3YOe2awrHygurzhO/HeQ6laiA6Sx0=
gotest.tools/v3 v3.0.3/go.mod h1:Z7Lb0S5l+klDB31fvDQX8ss/FlKDxtlFlw3Oa8Ymbl8=
helm.sh/helm/v3 v3.16.2 h1:Y9v7ry+ubQmi+cb5zw1Llx8OKHU9Hk9NQ/+P+LGBe2o=

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In diesem Beispiel wird es ganz einfach sein. Nehmen wir jedoch an, dass wir, da sie mit anderen Projekten in der Organisation geteilt wird, sie nicht ändern und kein `prefix`, `dependencies`, `tags`, usw. direkt zum `APIRouter` hinzufügen können:

```Python hl_lines="3" title="app/internal/admin.py"
{!../../docs_src/bigger_applications/app/internal/admin.py!}

If you can use the **latest versions of Python**, use the examples for the latest version, those will have the **best and simplest syntax**, for example, "**Python 3.10+**".

#### List

For example, let's define a variable to be a `list` of `str`.

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