{* ../../docs_src/header_param_models/tutorial001_an_py310.py hl[9:14,18] *}

**FastAPI** will **extract** the data for **each field** from the **headers** in the request and give you the Pydantic model you defined.

## Check the Docs { #check-the-docs }

You can see the required headers in the docs UI at `/docs`:

<div class="screenshot">
<img src="/img/tutorial/header-param-models/image01.png">
</div>

type Source struct {
	Host      string `json:"host"`
	Port      string `json:"port"`
	UserAgent string `json:"userAgent"`
}

// Event represents event notification information defined in
// http://docs.aws.amazon.com/AmazonS3/latest/dev/notification-content-structure.html.
type Event struct {
	EventVersion      string            `json:"eventVersion"`
	EventSource       string            `json:"eventSource"`

Vendoring in std and cmd
========================

The Go command maintains copies of external packages needed by the
standard library in the src/vendor and src/cmd/vendor directories.

There are two modules, std and cmd, defined in src/go.mod and
src/cmd/go.mod. When a package outside std or cmd is imported
by a package inside std or cmd, the import path is interpreted
as if it had a "vendor/" prefix. For example, within "crypto/tls",

import static java.lang.annotation.ElementType.ANNOTATION_TYPE;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * Meta-annotation that marks other annotations as scope annotations.
 * <p>
 * Scopes define the lifecycle and visibility of objects in the dependency injection
 * system. Custom scope annotations should be annotated with {@code @Scope}.
 * <p>
 * Built-in scopes include:
 * <ul>

// the [Scanner.Scan] method will step through the 'tokens' of a file, skipping
// the bytes between the tokens. The specification of a token is
// defined by a split function of type [SplitFunc]; the default split
// function breaks the input into lines with line termination stripped. [Scanner.Split]
// functions are defined in this package for scanning a file into
// lines, bytes, UTF-8-encoded runes, and space-delimited words. The

@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"

@rem Find java.exe
if defined JAVA_HOME goto findJavaFromJavaHome

set JAVA_EXE=java.exe
%JAVA_EXE% -version >NUL 2>&1
if %ERRORLEVEL% equ 0 goto execute

echo. 1>&2

```

**Note:** Execute the commands on all 4 nodes.

![Example-3](https://github.com/minio/minio/blob/master/docs/screenshots/Example-3.jpg?raw=true)

 * specified the JVM flag {@code -XX:+DisableExplicitGC}. But in practice, it works very well for
 * ordinary tests.
 *
 * <p>Failure of the expected event to occur within an implementation-defined "reasonable" time
 * period or an interrupt while waiting for the expected event will result in a {@link
 * RuntimeException}.
 *
 * <p>Here's an example that tests a {@code finalize} method:
 *
 * {@snippet :

            options.addOption(Option.builder(CACHE_ARTIFACT_NOT_FOUND)
                    .longOpt("cache-artifact-not-found")
                    .hasArg()
                    .desc(
                            "Defines caching behaviour for 'not found' artifacts. Supported values are 'true' (default), 'false'.")
                    .get());
            options.addOption(Option.builder(STRICT_ARTIFACT_DESCRIPTOR_POLICY)

    } catch (AssertionFailedError expected) {
      return;
    }
    fail("Should have failed");
  }

  /** An interface for the 2 ways that a chaining call might be defined. */
  private interface ChainingCalls {
    // A method that is defined to 'return this'
    @CanIgnoreReturnValue
    ChainingCalls chainingCall();

    // A method that just happens to return a ChainingCalls object