* Validation even for deeply nested JSON objects.
* <dfn title="also known as: serialization, parsing, marshalling">Conversion</dfn> of input data: coming from the network to Python data and types. Reading from:
    * JSON.
    * Path parameters.
    * Query parameters.
    * Cookies.
    * Headers.
    * Forms.
    * Files.

          BinaryOperator<V> mergeFunction) {
    checkNotNull(keyFunction);
    checkNotNull(valueFunction);
    checkNotNull(mergeFunction);
    // not UNORDERED because we don't know if mergeFunction is commutative
    return Collector.of(
        () -> new EnumMapAccumulator<K, V>(mergeFunction),
        (accum, t) -> {
          /*

          BinaryOperator<V> mergeFunction) {
    checkNotNull(keyFunction);
    checkNotNull(valueFunction);
    checkNotNull(mergeFunction);
    // not UNORDERED because we don't know if mergeFunction is commutative
    return Collector.of(
        () -> new EnumMapAccumulator<K, V>(mergeFunction),
        (accum, t) -> {
          /*

            }
            candidateSource = new FileModelSource(candidateModel.getPomFile());
        }

        //
        // TODO jvz Why isn't all this checking the job of the duty of the workspace resolver, we know that we
        // have a model that is suitable, yet more checks are done here and the one for the version is problematic
        // before because with parents as ranges it will never work in this scenario.
        //

Using Linux containers has several advantages including **security**, **replicability**, **simplicity**, and others.

/// tip

In a hurry and already know this stuff? Jump to the [`Dockerfile` below 👇](#build-a-docker-image-for-fastapi).

///

<details>
<summary>Dockerfile Preview 👀</summary>

```Dockerfile
FROM python:3.14

WORKDIR /code

These examples are intentionally simple, but show how it all works.

In the chapters about security, there are utility functions that are implemented in this same way.

If you understood all this, you already know how those utility tools for security work underneath.

///

## Dependencies with `yield`, `HTTPException`, `except` and Background Tasks { #dependencies-with-yield-httpexception-except-and-background-tasks }

/// warning

          return 0;
        }
        if (occurrences >= current) {
          if (countMap.remove(element, current)) {
            return current;
          }
        } else {
          // We know it's an "E" because it already exists in the map.
          @SuppressWarnings("unchecked")
          E casted = (E) element;

          if (countMap.replace(casted, current, current - occurrences)) {

complete object files to the recipients, so that they can relink them
with the library after making changes to the library and recompiling
it.  And you must show them these terms so they know their rights.

  We protect your rights with a two-step method: (1) we copyright the
library, and (2) we offer you this license, which gives you legal
permission to copy, distribute and/or modify the library.

     * and then to XOR them together.  The strideTable enables us to hash an int followed by 12
     * zero bytes (3 ints), while the byteTable is for advancing one byte at a time.
     * This algorithm is due to the paper "Everything we know about CRC but [are] afraid to forget"
     * by Kadatch and Jenkins, 2010.
     */

    Crc32cHasher() {
      super(16);
    }

    private boolean finished = false;

    /*

```bash
fastapi dev
```


Run the production server:

```bash
fastapi run
```

### Add an entrypoint in `pyproject.toml`

FastAPI CLI will read the entrypoint in `pyproject.toml` to know where the FastAPI app is declared.

```toml
[tool.fastapi]
entrypoint = "my_app.main:app"
```

### Use `fastapi` with a path