}

  /**
   * Creates a <i>mutable</i>, empty {@code HashMap} instance.
   *
   * <p><b>Note:</b> if mutability is not required, use {@link ImmutableMap#of()} instead.
   *
   * <p><b>Note:</b> if {@code K} is an {@code enum} type, use {@link #newEnumMap} instead.
   *
   * <p><b>Note:</b> this method is now unnecessary and should be treated as deprecated. Instead,

import java.lang.annotation.Target;
import javax.annotation.Nonnull;
import javax.annotation.meta.TypeQualifierDefault;

/**
 * Marks all "top-level" types as non-null in a way that is recognized by Kotlin. Note that this
 * unfortunately includes type-variable usages, so we also provide {@link ParametricNullness} to
 * "undo" it as best we can.
 */
@GwtCompatible
@Retention(RUNTIME)
@Target(TYPE)

import java.lang.annotation.Target;
import javax.annotation.Nonnull;
import javax.annotation.meta.TypeQualifierDefault;

/**
 * Marks all "top-level" types as non-null in a way that is recognized by Kotlin. Note that this
 * unfortunately includes type-variable usages, so we also provide {@link ParametricNullness} to
 * "undo" it as best we can.
 */
@GwtCompatible
@Retention(RUNTIME)
@Target(TYPE)

import java.lang.annotation.Target;
import javax.annotation.Nonnull;
import javax.annotation.meta.TypeQualifierDefault;

/**
 * Marks all "top-level" types as non-null in a way that is recognized by Kotlin. Note that this
 * unfortunately includes type-variable usages, so we also provide {@link ParametricNullness} to
 * "undo" it as best we can.
 */
@GwtCompatible
@Retention(RUNTIME)
@Target(TYPE)

import java.lang.annotation.Target;
import javax.annotation.Nonnull;
import javax.annotation.meta.TypeQualifierDefault;

/**
 * Marks all "top-level" types as non-null in a way that is recognized by Kotlin. Note that this
 * unfortunately includes type-variable usages, so we also provide {@link ParametricNullness} to
 * "undo" it as best we can.
 */
@GwtCompatible
@Retention(RUNTIME)
@Target(TYPE)

import java.lang.annotation.Target;
import javax.annotation.Nonnull;
import javax.annotation.meta.TypeQualifierDefault;

/**
 * Marks all "top-level" types as non-null in a way that is recognized by Kotlin. Note that this
 * unfortunately includes type-variable usages, so we also provide {@link ParametricNullness} to
 * "undo" it as best we can.
 */
@GwtCompatible
@Retention(RUNTIME)
@Target(TYPE)

////

//// tab | 🐍 3️⃣.1️⃣0️⃣ & 🔛

```Python hl_lines="9-12"
{!> ../../docs_src/body_fields/tutorial001_py310.py!}
```

////

`Field` 👷 🎏 🌌 `Query`, `Path` & `Body`, ⚫️ ✔️ 🌐 🎏 🔢, ♒️.

/// note | "📡 ℹ"

🤙, `Query`, `Path` & 🎏 👆 🔜 👀 ⏭ ✍ 🎚 🏿 ⚠ `Param` 🎓, ❔ ⚫️ 🏿 Pydantic `FieldInfo` 🎓.

 & Pydantic `Field` 📨 👐 `FieldInfo` 👍.

🔰, 👆 💪 💚 ❎ ⚫️ ⏮️ 🌐 📦 🔗 & ⚒:

<div class="termy">

```console
$ pip install "fastapi[all]"

---> 100%
```

</div>

...👈 🔌 `uvicorn`, 👈 👆 💪 ⚙️ 💽 👈 🏃 👆 📟.

/// note

👆 💪 ❎ ⚫️ 🍕 🍕.

👉 ⚫️❔ 👆 🔜 🎲 🕐 👆 💚 🛠️ 👆 🈸 🏭:

```
pip install "fastapi[standard]"
```

❎ `uvicorn` 👷 💽:

```
pip install "uvicorn[standard]"
```

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.

/// note | "Technical Details"

Actually, `Query`, `Path` and others you'll see next create objects of subclasses of a common `Param` class, which is itself a subclass of Pydantic's `FieldInfo` class.

import typing

from fastapi import Body, FastAPI
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()

media_type = "application/vnd.api+json"


# NOTE: These are not valid JSON:API resources
# but they are fine for testing requestBody with custom media_type
class Product(BaseModel):
    name: str
    price: float


class Shop(BaseModel):
    name: str


@app.post("/products")