The important thing to remember is that **the first *type parameter*** you pass to `Annotated` is the **actual type**. The rest, is just metadata for other tools.

For now, you just need to know that `Annotated` exists, and that it's standard Python. 😎

Later you will see how **powerful** it can be.

/// tip

<div style="text-align: right; margin-right: 10%;">Kabir Khan - <strong>Microsoft</strong> <a href="https://github.com/fastapi/fastapi/pull/26"><small>(ref)</small></a></div>

---

"_We adopted the **FastAPI** library to spawn a **REST** server that can be queried to obtain **predictions**. [for Ludwig]_"

<div style="text-align: right; margin-right: 10%;">Kabir Khan - <strong>Microsoft</strong> <a href="https://github.com/fastapi/fastapi/pull/26"><small>(ref)</small></a></div>

---

"_我們採用了 **FastAPI** 函式庫來啟動一個 **REST** 伺服器，供查詢以取得**預測**。[for Ludwig]_"

<div style="text-align: right; margin-right: 10%;">Piero Molino, Yaroslav Dudin, and Sai Sumanth Miryala - <strong>Uber</strong> <a href="https://eng.uber.com/ludwig-v0-2/"><small>(ref)</small></a></div>

    This is where we'll put the `requirements.txt` file and the `app` directory.

3. Copy the file with the requirements to the `/code` directory.

    Copy **only** the file with the requirements first, not the rest of the code.

    As this file **doesn't change often**, Docker will detect it and use the **cache** for this step, enabling the cache for the next step too.

4. Install the package dependencies in the requirements file.

Then, using the certificate, the client and the TLS Termination Proxy **decide how to encrypt** the rest of the **TCP communication**. This completes the **TLS Handshake** part.

///

## Types and validation { #types-and-validation }

These environment variables can only handle text strings, as they are external to Python and have to be compatible with other programs and the rest of the system (and even with different operating systems, as Linux, Windows, macOS).

L'important à retenir est que **le premier « paramètre de type »** que vous passez à `Annotated` est le **type réel**. Le reste n'est que des métadonnées pour d'autres outils.

Pour l'instant, vous avez juste besoin de savoir que `Annotated` existe, et que c'est du Python standard. 😎

Plus tard, vous verrez à quel point cela peut être **puissant**.

                field_dict["annotation"],
                *field_dict["metadata"],
                # this FieldInfo needs to be created again so that it doesn't include
                # the old field info metadata and only the rest of the attributes
                Field(**field_dict["attributes"]),
            )
            self._type_adapter: TypeAdapter[Any] = TypeAdapter(
                Annotated[annotated_args],  # ty: ignore[invalid-type-form]

      byte[] buf = new byte[min(bufSize, MAX_ARRAY_LEN - totalLen)];
      bufs.add(buf);
      int off = 0;
      while (off < buf.length) {
        // always OK to fill buf; its size plus the rest of bufs is never more than MAX_ARRAY_LEN
        int r = in.read(buf, off, buf.length - off);
        if (r == -1) {
          return combineBuffers(bufs, totalLen);
        }
        off += r;
        totalLen += r;

  This question the Dodo could not answer without a great deal of
thought, and it sat for a long time with one finger pressed upon
its forehead (the position in which you usually see Shakespeare,
in the pictures of him), while the rest waited in silence.  At
last the Dodo said, `EVERYBODY has won, and all must have
prizes.'

  `But who is to give the prizes?' quite a chorus of voices
asked.