So, a Python class is also a **callable**.

Then, in **FastAPI**, you could use a Python class as a dependency.

What FastAPI actually checks is that it is a "callable" (function, class or anything else) and the parameters defined.

If you pass a "callable" as a dependency in **FastAPI**, it will analyze the parameters for that "callable", and process them in the same way as the parameters for a *path operation function*. Including sub-dependencies.

    NEXT_HIGHER {
      @Override
      public int resultIndex(int higherIndex) {
        return higherIndex;
      }
    },
    /**
     * Return {@code ~insertionIndex}, where {@code insertionIndex} is defined as the point at which
     * the key would be inserted into the list: the index of the next higher element in the list, or
     * {@code list.size()} if there is no such element.
     *

   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION

   1. Definitions.

      "License" shall mean the terms and conditions for use, reproduction,
      and distribution as defined by Sections 1 through 9 of this document.

      "Licensor" shall mean the copyright owner or entity authorized by
      the copyright owner that is granting the License.

  }

  @SuppressWarnings("rawtypes") // TreeBasedTable.create() is defined as such
  @Generates
  static <R extends Comparable, C extends Comparable, V>
      RowSortedTable<R, C, V> generateRowSortedTable(R row, C column, V value) {
    return generateTreeBasedTable(row, column, value);
  }

  @SuppressWarnings("rawtypes") // TreeBasedTable.create() is defined as such
  @Generates

   * whose keys and values are the result of applying the provided mapping functions to the input
   * elements.
   *
   * <p>For streams with defined encounter order (as defined in the Ordering section of the {@link
   * java.util.stream} Javadoc), that order is preserved, but entries are <a
   * href="ImmutableMultimap.html#iteration">grouped by key</a>.
   *
   * <p>Example:
   *

 * closely related, e.g. see <a href="http://en.wikipedia.org/wiki/Little%27s_law">Little's
 * Law</a>).
 *
 * <p>A {@code RateLimiter} is defined primarily by the rate at which permits are issued. Absent
 * additional configuration, permits will be distributed at a fixed rate, defined in terms of
 * permits per second. Permits will be distributed smoothly, with the delay between individual

  // +patchMergeKey=type
  // +patchStrategy=merge
  // +listType=map
  // +listMapKey=type
  // +optional
  repeated HorizontalPodAutoscalerCondition conditions = 6;
}

// MetricIdentifier defines the name and optionally selector for a metric
message MetricIdentifier {
  // name is the name of the given metric
  optional string name = 1;

 * "numbers") into two sections; this can be done below a certain value, above a certain value,
 * below all values or above all values. With this object defined in this way, an interval can
 * always be represented by a pair of {@code Cut} instances.
 *
 * @author Kevin Bourrillion
 */
@SuppressWarnings("rawtypes") // https://github.com/google/guava/issues/989
@GwtCompatible

```

C'est une fonction Python.

Elle sera appelée par **FastAPI** quand une requête sur l'URL `/` sera reçue via une opération `GET`.

Ici, c'est une fonction asynchrone (définie avec `async def`).

---

Vous pourriez aussi la définir comme une fonction classique plutôt qu'avec `async def` :

```Python hl_lines="7"
{!../../docs_src/first_steps/tutorial003.py!}
```

/// note

   | value of '1.4' might activate a profile when the build is executed on a JDK version of '1.4.2_07'.
   | Finally, the list of active profiles can be specified directly from the command line.
   |
   | NOTE: For profiles defined in the settings.xml, you are restricted to specifying only artifact
   |       repositories, plugin repositories, and free-form properties to be used as configuration
   |       variables for plugins in the POM.
   |
   |-->