/// warning

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

///

## Declare model attributes { #declare-model-attributes }

You can then use `Field` with model attributes:

{* ../../docs_src/body_fields/tutorial001_an_py310.py hl[11:14] *}

`Field` works the same way as `Query`, `Path` and `Body`, it has all the same parameters, etc.

            doc.superClass = superDoc
            doc.interfaces << superType1
            doc.interfaces << superType2
            builder.build(doc)
            return doc
        }

        then:
        doc.classProperties.size() == 5
        doc.classProperties[0].name == 'a'
        doc.classProperties[1].name == 'b'
        doc.classProperties[2].name == 'c'
        doc.classProperties[3].name == 'd'

### Model for Input { #model-for-input }

If you use this model as an input like here:

{* ../../docs_src/separate_openapi_schemas/tutorial001_py310.py ln[1:15] hl[14] *}

...then the `description` field will **not be required**. Because it has a default value of `None`.

### Input Model in Docs { #input-model-in-docs }

# limitations under the License.
# ==============================================================================

"""Extracts ResultStore links from a log containing Bazel invocations.

The links and the invocations' status can then be printed out, or output in the
form of JUnit-based XML.
"""
import argparse
import datetime
import os
import re
from typing import Dict, Union
import xml.etree.ElementTree as ElemTree

	Tags    []Tag    `xml:"Tag,omitempty" json:"Tag,omitempty"`
}

var errDuplicateTagKey = Errorf("Duplicate Tag Keys are not allowed")

// isEmpty returns true if Tags field is null
func (a And) isEmpty() bool {
	return len(a.Tags) == 0 && a.Prefix == ""
}

// Validate - validates the And field
func (a And) Validate() error {
	if a.ContainsDuplicateTag() {
		return errDuplicateTagKey
	}
	for _, t := range a.Tags {

# Note that we must use nightly here as these are used in nightly jobs
# For release jobs, we will pin these on the release branch
keras-nightly ~= 3.10.0.dev
tb-nightly ~= 2.20.0.a
# For new protobuf, if V.x.y is gencode version, then runtime version U must be
# V <= U <= V+1
# More info at https://protobuf.dev/support/cross-version-runtime-guarantee/
protobuf >= 5.28.0, < 7.0
# Test dependencies
grpcio >= 1.68.1, < 2.0
portpicker == 1.6.0

# If no prefix is passed, by default, it's replaced with C:\, in case it's
# something else (ex. T:), which is a volume used in internal CI.
function replace_drive_letter_with_prefix () {
  local path_prefix
  if [[ -z "$2" ]]; then
    path_prefix="C:"
  else
    path_prefix="$2"
  fi
  sed -E "s|^[a-zA-Z]:|${path_prefix}|g" <<< "$1"

	// latency and update its and all subsequent counters.
	bucket := slices.IndexFunc(k.latencyBuckets, func(b time.Duration) bool { return latency < b })
	if bucket < 0 {
		bucket = len(k.latencyBuckets) - 1
	}
	for i := bucket; i < len(k.latency); i++ {
		k.latency[i].Add(1)
	}

	// Next, update the request counters
	if err == nil {
		k.reqOK.Add(1)
		return
	}

	var s3Err Error

        // replaces?
        AbstractRepositoryMetadata repoMetadata = (AbstractRepositoryMetadata) metadata;
        this.metadata.merge(repoMetadata.getMetadata());
    }

    @Override
    public void merge(ArtifactMetadata metadata) {
        // TODO not sure that it should assume this, maybe the calls to addMetadata should pre-merge, then artifact
        // replaces?

In this case, **FastAPI** will notice that there is more than one body parameter in the function (there are two parameters that are Pydantic models).

So, it will then use the parameter names as keys (field names) in the body, and expect a body like:

```JSON
{
    "item": {
        "name": "Foo",
        "description": "The pretender",
        "price": 42.0,
        "tax": 3.2