If for some reason you need to disable automatic conversion of underscores to hyphens, set the parameter `convert_underscores` of `Header` to `False`:

//// tab | Python 3.10+

```Python hl_lines="10"
{!> ../../docs_src/header_params/tutorial002_an_py310.py!}
```

////

//// tab | Python 3.9+

import (
	"strconv"

	"github.com/minio/minio/internal/bucket/lifecycle"
)

//go:generate stringer -type lcEventSrc -trimprefix lcEventSrc_ $GOFILE
type lcEventSrc uint8

//revive:disable:var-naming Underscores is used here to indicate where common prefix ends and the enumeration name begins
const (
	lcEventSrc_None lcEventSrc = iota
	lcEventSrc_Heal
	lcEventSrc_Scanner
	lcEventSrc_Decom
	lcEventSrc_Rebal

     * <p>ASCII characters in the part are expected to be valid per RFC 1035, with underscore also
     * being allowed due to widespread practice.
     */

    String asciiChars = CharMatcher.ascii().retainFrom(part);

    if (!PART_CHAR_MATCHER.matchesAllOf(asciiChars)) {
      return false;
    }

    // No initial or final dashes or underscores.

    if (DASH_MATCHER.matches(part.charAt(0))

     * <p>ASCII characters in the part are expected to be valid per RFC 1035, with underscore also
     * being allowed due to widespread practice.
     */

    String asciiChars = CharMatcher.ascii().retainFrom(part);

    if (!PART_CHAR_MATCHER.matchesAllOf(asciiChars)) {
      return false;
    }

    // No initial or final dashes or underscores.

    if (DASH_MATCHER.matches(part.charAt(0))

            """
        ),
    ] = None,
    convert_underscores: Annotated[
        bool,
        Doc(
            """
            Automatically convert underscores to hyphens in the parameter field name.

            Read more about it in the
            [FastAPI docs for Header Parameters](https://fastapi.tiangolo.com/tutorial/header-params/#automatic-conversion)
            """

ldap.admin.group.object.classes=groupOfNames
ldap.admin.sync.password=true

ldap.auth.validation=true
ldap.max.username.length=-1
ldap.ignore.netbios.name=true
ldap.group.name.with.underscores=false
ldap.lowercase.permission.name=false
ldap.allow.empty.permission=true

ldap.role.search.user.enabled=true
ldap.role.search.group.enabled=true
ldap.role.search.role.enabled=true

and <code>A</code> through <code>F</code> represent values 10 through 15.
</p>

<p>
For readability, an underscore character <code>_</code> may appear after
a base prefix or between successive digits; such underscores do not change
the literal's value.
</p>
<pre class="ebnf">
int_lit        = decimal_lit | binary_lit | octal_lit | hex_lit .

    /**
     * Get the value for the key 'ldap.group.name.with.underscores'. <br>
     * The value is, e.g. false <br>
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getLdapGroupNameWithUnderscores();

    /**
     * Is the property for the key 'ldap.group.name.with.underscores' true? <br>
     * The value is, e.g. false <br>

and <code>A</code> through <code>F</code> represent values 10 through 15.
</p>

<p>
For readability, an underscore character <code>_</code> may appear after
a base prefix or between successive digits; such underscores do not change
the literal's value.
</p>
<pre class="ebnf">
int_lit        = decimal_lit | binary_lit | octal_lit | hex_lit .

            {"strange_header": "FastAPI test"},
            200,
            {"strange_header": "FastAPI test"},
        ),
        (
            "/items",
            {"strange-header": "Not really underscore"},
            200,
            {"strange_header": None},
        ),
    ],
)
def test(path, headers, expected_status, expected_response):
    response = client.get(path, headers=headers)