Remember I told you before that `Annotated` can be used to add metadata to your parameters in the [Python Types Intro](../python-types.md#type-hints-with-metadata-annotations){.internal-link target=_blank}?

Now it's the time to use it with FastAPI. 🚀

We had this type annotation:

//// tab | Python 3.10+

```Python
q: str | None = None
```

////

//// tab | Python 3.9+

```Python
q: Union[str, None] = None

---

"_**FastAPI** için ayın üzerindeymişcesine heyecanlıyım. Çok eğlenceli!_"

<div style="text-align: right; margin-right: 10%;">Brian Okken - <strong><a href="https://pythonbytes.fm/episodes/show/123/time-to-right-the-py-wrongs?time_in_sec=855" target="_blank">Python Bytes</a> podcast host</strong> <a href="https://x.com/brianokken/status/1112220079972728832" target="_blank"><small>(ref)</small></a></div>

---

        <field>
          <name>defaultValue</name>
          <version>2.0.0+</version>
          <type>String</type>
          <description>The default value, as an expression that will be evaluated at injection or run-time.</description>
        </field>
      </fields>
    </class>

    <class xdoc.anchorName="requirement">
      <name>Requirement</name>
      <version>1.0.0/1.1.0</version>

      the inputs received by the layer and the eviction policy. When this layer
      is used with an `UpdateEmbeddingCallback`, which is a time-based callback,
      the vocabulary lookup tensor is updated at the time interval set in the
      `UpdateEmbeddingCallback` based on the most up-to-date vocabulary hash
      table maintained by the layer. If this layer is not used in conjunction

golang.org/x/text v0.24.0/go.mod h1:L8rBsPeo2pSS+xqN0d5u2ikmjtmoJbDBT1b7nHvFCdU=
golang.org/x/time v0.0.0-20211116232009-f0f3c7e86c11/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
golang.org/x/time v0.11.0 h1:/bpjEDfN9tkoN/ryeYHnv5hcMlc8ncjMcM4XBk5NWV0=
golang.org/x/time v0.11.0/go.mod h1:CDIdPxbZBQxdj6cxyCIdrNogrJKMJ7pr37NYpMcMDSg=

---

"_Je suis très enthousiaste à propos de **FastAPI**. C'est un bonheur !_"

<div style="text-align: right; margin-right: 10%;">Brian Okken - <strong>Auteur du podcast <a href="https://pythonbytes.fm/episodes/show/123/time-to-right-the-py-wrongs?time_in_sec=855" target="_blank">Python Bytes</a></strong> <a href="https://x.com/brianokken/status/1112220079972728832" target="_blank"><small>(ref)</small></a></div>

---

---

"_Estoy súper emocionado con **FastAPI**. ¡Es tan divertido!_"

<div style="text-align: right; margin-right: 10%;">Brian Okken - <strong><a href="https://pythonbytes.fm/episodes/show/123/time-to-right-the-py-wrongs?time_in_sec=855" target="_blank">host del podcast Python Bytes</a></strong> <a href="https://x.com/brianokken/status/1112220079972728832" target="_blank"><small>(ref)</small></a></div>

---

---

"_我對 **FastAPI** 興奮得不得了。它太有趣了！_"

<div style="text-align: right; margin-right: 10%;">Brian Okken - <strong><a href="https://pythonbytes.fm/episodes/show/123/time-to-right-the-py-wrongs?time_in_sec=855" target="_blank">Python Bytes</a> podcast host</strong> <a href="https://x.com/brianokken/status/1112220079972728832" target="_blank"><small>(ref)</small></a></div>

---

---

"*Estou extremamente entusiasmado com o **FastAPI**. É tão divertido!*"

<div style="text-align: right; margin-right: 10%;">Brian Okken - <strong><a href="https://pythonbytes.fm/episodes/show/123/time-to-right-the-py-wrongs?time_in_sec=855" target="_blank">Python Bytes</a> podcaster</strong> <a href="https://x.com/brianokken/status/1112220079972728832" target="_blank"><small>(ref)</small></a></div>

---

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