### Étape 1 : import `FastAPI`

{* ../../docs_src/first_steps/tutorial001.py hl[1] *}

`FastAPI` est une classe Python qui fournit toutes les fonctionnalités nécessaires au lancement de votre API.

/// note | Détails techniques

`FastAPI` est une classe héritant directement de `Starlette`.

// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"context"
	"encoding/json"

When you declare a *path operation* in your application, **FastAPI** automatically generates the relevant metadata about that *path operation* to be included in the OpenAPI schema.

/// note | Technical details

In the OpenAPI specification it is called the <a href="https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.0.3.md#operation-object" class="external-link" target="_blank">Operation Object</a>.

///

Tous partagent les mêmes paramètres pour des validations supplémentaires et des métadonnées que vous avez vu précédemment.

///

/// note | Détails techniques

Lorsque vous importez `Query`, `Path` et d'autres de `fastapi`, ce sont en fait des fonctions.

Ces dernières, lorsqu'elles sont appelées, renvoient des instances de classes du même nom.

// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"bytes"
	"crypto/rand"
	"io"

// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package event

import (
	"encoding/xml"
	"errors"

// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package target

import (
	"crypto/tls"
	"crypto/x509"

// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package replication

import (
	"bytes"
	"encoding/xml"

                      See <a href="https://bt-internal-docs.grdev.net/gbt/how-to/release/release-troubleshooting/#binary-compatibility-check-failed-">the documentation</a> for more details.
                  </div>
                </div>
                </p>
                <p>
                If change was made on the `release` branch but hasn't yet been merged to `master`, merge `release` to `master`:

Com `openapi_examples` adicionado a `Body()`, o `/docs` ficaria assim:

<img src="/img/tutorial/body-fields/image02.png">

## Detalhes Técnicos { #technical-details }

/// tip | Dica

Se você já está usando o **FastAPI** na versão **0.99.0 ou superior**, você provavelmente pode **pular** esses detalhes.