## Import `Field`

First, you have to import it:

{* ../../docs_src/body_fields/tutorial001_an_py310.py hl[4] *}


/// warning

Notice that `Field` is imported directly from `pydantic`, not from `fastapi` as are all the rest (`Query`, `Path`, `Body`, etc).

///

## Declare model attributes

    return x * 42


ml_models = {}


@asynccontextmanager
async def lifespan(app: FastAPI):
    # Load the ML model
    ml_models["answer_to_everything"] = fake_answer_to_everything_ml_model
    yield
    # Clean up the ML models and release the resources
    ml_models.clear()


app = FastAPI(lifespan=lifespan)


@app.get("/predict")
async def predict(x: float):

from fastapi.openapi.models import SecurityBase as SecurityBaseModel


class SecurityBase:
    model: SecurityBaseModel

 *  * `com.twitter.hpack.HpackUtil`
 *
 * [twitter_hpack]: https://github.com/twitter/hpack
 */
object Huffman {
  // Appendix C: Huffman Codes
  // http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-12#appendix-B
  private val CODES =
    intArrayOf(
      0x1ff8, 0x7fffd8, 0xfffffe2, 0xfffffe3, 0xfffffe4, 0xfffffe5, 0xfffffe6,

///

### Pydantic and FastAPI `examples`

When you add `examples` inside a Pydantic model, using `schema_extra` or `Field(examples=["something"])` that example is added to the **JSON Schema** for that Pydantic model.

And that **JSON Schema** of the Pydantic model is included in the **OpenAPI** of your API, and then it's used in the docs UI.

from typing import Optional

from fastapi.openapi.models import OpenIdConnect as OpenIdConnectModel
from fastapi.security.base import SecurityBase
from starlette.exceptions import HTTPException
from starlette.requests import Request
from starlette.status import HTTP_403_FORBIDDEN
from typing_extensions import Annotated, Doc


class OpenIdConnect(SecurityBase):
    """
    OpenID Connect authentication class. An instance of it would be used as a

 * under the License.
 */
package org.apache.maven.model.building;

import java.io.File;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Properties;

import org.apache.maven.model.Model;
import org.apache.maven.model.Profile;
import org.apache.maven.model.resolution.ModelResolver;
import org.apache.maven.model.resolution.WorkspaceModelResolver;

/**

            @Override
            public Model getRawModel(Path from, String gId, String aId) {
                Model model = findRawModel(from, gId, aId);
                if (model != null) {
                    context.modelByGA.put(new GAKey(gId, aId), new Holder(model));
                    context.modelByPath.put(model.getPomPath(), new Holder(model));
                }
                return model;
            }

            @Override

    "functionalTests": true,
    "crossVersionTests": false
  },
  {
    "name": "model-core",
    "path": "platforms/core-configuration/model-core",
    "unitTests": true,
    "functionalTests": true,
    "crossVersionTests": false
  },
  {
    "name": "model-groovy",
    "path": "platforms/core-configuration/model-groovy",
    "unitTests": true,
    "functionalTests": true,
    "crossVersionTests": false

## 0.30.0

* Add support for Pydantic's ORM mode:
    * Updated documentation about SQL with SQLAlchemy, using Pydantic models with ORM mode, SQLAlchemy models with relations, separation of files, simplification of code and other changes. New docs: [SQL (Relational) Databases](https://fastapi.tiangolo.com/tutorial/sql-databases/).