You could load it at the top level of the module/file, but that would also mean that it would **load the model** even if you are just running a simple automated test, then that test would be **slow** because it would have to wait for the model to load before being able to run an independent part of the code.

     */
    PERSISTENT,

    /**
     * Data should be retained for the duration of the current Maven session.
     * Suitable for:
     * - Build-wide configuration
     * - Project model caching
     * - Inter-module metadata
     */
    SESSION_SCOPED,

    /**
     * Data should only be retained for the current build request.
     * Suitable for:
     * - Plugin execution results

## Nested Models { #nested-models }

Each attribute of a Pydantic model has a type.

But that type can itself be another Pydantic model.

So, you can declare deeply nested JSON "objects" with specific attribute names, types and validations.

All that, arbitrarily nested.

### Define a submodel { #define-a-submodel }

For example, we can define an `Image` model:

{* ../../docs_src/body_nested_models/tutorial004_py310.py hl[7:9] *}

!function(a,b){"function"==typeof define&&define.amd?define(["jquery"],function(a){return b(a)}):"object"==typeof module&&module.exports?module.exports=b(require("jquery")):b(a.jQuery)}(this,function(a){!function(a,b){"use strict";a.formUtils.registerLoadedModule("lang/it"),a(b).bind("validatorsLoaded",function(){a.formUtils.LANG={errorTitle:"Impossibile inviare il modulo!",requiredField:"Campo obbligatorio",requiredFields:"Non sono stati compilati tutti i campi richiesti",badTime:"L'ora scelta...

     * If the JAR is modular, its module information are ignored.
     * This type is new in Maven 4.
     */
    String CLASSPATH_JAR = "classpath-jar";

    /**
     * Artifact type name for a JAR file to unconditionally place on the module path.
     * If the JAR is not modular, then it is loaded by Java as an unnamed module.
     * This type is new in Maven 4.
     */

            <artifactId>jackson-databind</artifactId>
            <version>${jackson.version}</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.module</groupId>
            <artifactId>jackson-module-kotlin</artifactId>
            <version>${jackson.version}</version>
        </dependency>
        <dependency>
            <groupId>com.google.code.gson</groupId>

  <ciManagement>
    <system>GitHub Actions</system>
    <url>https://github.com/google/guava/actions</url>
  </ciManagement>
  <modules>
    <module>guava</module>
    <module>guava-bom</module>
    <module>guava-gwt</module>
    <module>guava-testlib</module>
    <module>guava-tests</module>
  </modules>
  <build>
    <!-- Handle where Guava deviates from Maven defaults -->
    <sourceDirectory>src</sourceDirectory>

        <h2>Default source directories</h2>
        If no source directories are specified, the default values depend on whether module names are specified:
        <ul>
          <li>{@code src/${scope}/${lang}} if no module is specified</li>
          <li>{@code src/${module}/${scope}/${lang}} if a module is specified</li>
        </ul>
        where

   <span style="background-color:#007166"><font color="#D3D7CF"> module </font></span>  🐍 main.py

     <span style="background-color:#007166"><font color="#D3D7CF"> code </font></span>  Importing the FastAPI app object from the module with
             the following code:

  </developers>
  <ciManagement>
    <system>GitHub Actions</system>
    <url>https://github.com/google/guava/actions</url>
  </ciManagement>
  <modules>
    <module>guava</module>
    <module>guava-bom</module>
    <module>guava-testlib</module>
    <module>guava-tests</module>
  </modules>
  <build>
    <!-- Handle where Guava deviates from Maven defaults -->
    <sourceDirectory>src</sourceDirectory>