For example, let's add <a href="https://github.com/Rebilly/ReDoc/blob/master/docs/redoc-vendor-extensions.md#x-logo" class="external-link" target="_blank">ReDoc's OpenAPI extension to include a custom logo</a>.

### Normal **FastAPI**

First, write all your **FastAPI** application as normally:

{* ../../docs_src/extending_openapi/tutorial001.py hl[1,4,7:9] *}

### Generate the OpenAPI schema

    Read more about it in the
    [FastAPI docs for Configure Swagger UI](https://fastapi.tiangolo.com/how-to/configure-swagger-ui/)
    and the [FastAPI docs for Custom Docs UI Static Assets (Self-Hosting)](https://fastapi.tiangolo.com/how-to/custom-docs-ui-assets/).
    """
    current_swagger_ui_parameters = swagger_ui_default_parameters.copy()
    if swagger_ui_parameters:

    "${testType.name.toCapitalized()}${testJvmVersion.name.toCapitalized()}${vendor.displayName}${os.asName()}${arch.asName()}"

// Generates a build scan custom value "PartOf=X,Y,Z"
// where X, Y, Z are all the stages including current stage
// For example, for the stage PullRequestFeedback, the custom value will be "PartOf=PullRequestFeedback,ReadyForNightly,ReadyForRelease"
private fun Stage.getBuildScanCustomValues(): List<String> {

    protocols: List<Protocol>,
  ) {
    // No TLS extensions if the socket class is custom.
    socketAdapters.find { it.matchesSocket(sslSocket) }
      ?.configureTlsExtensions(sslSocket, hostname, protocols)
  }

  override fun getSelectedProtocol(sslSocket: SSLSocket): String? =
    // No TLS extensions if the socket class is custom.
    socketAdapters.find { it.matchesSocket(sslSocket) }?.getSelectedProtocol(sslSocket)

# For most projects, this workflow file will not need changing; you simply need
# to commit it to your repository.
#
# You may wish to alter this file to override the set of languages analyzed,
# or to provide custom queries or build logic.
name: "CodeQL"

on:
  push:
    branches: [master]
  pull_request:
    # The branches below must be a subset of the branches above
    branches: [master]
  schedule:
    - cron: '0 9 * * 3'

jobs:

# For most projects, this workflow file will not need changing; you simply need
# to commit it to your repository.
#
# You may wish to alter this file to override the set of languages analyzed,
# or to provide custom queries or build logic.
name: "CodeQL"

on:
  push:
    branches: [master]
  pull_request:
    # The branches below must be a subset of the branches above
    branches: [master]
  schedule:
    - cron: '0 11 * * 4'

jobs:

	return fmt.Sprintf("%s%s", c.prefix, fieldValue), nil
}

func TestSerializer(t *testing.T) {
	schema.RegisterSerializer("custom", NewCustomSerializer("hello"))
	DB.Migrator().DropTable(adaptorSerializerModel(&SerializerStruct{}))
	if err := DB.Migrator().AutoMigrate(adaptorSerializerModel(&SerializerStruct{})); err != nil {

      else -> null // No TLS extensions if the socket class is custom.
    }

  override fun configureTlsExtensions(
    sslSocket: SSLSocket,
    hostname: String?,
    protocols: List<Protocol>,
  ) {
    // No TLS extensions if the socket class is custom.
    if (matchesSocket(sslSocket)) {
      // Enable session tickets.
      Conscrypt.setUseSessionTickets(sslSocket, true)

import (
	"context"
	"net"
	"time"
)

// LookupHost is a function to make custom lookupHost for optional cached DNS requests
type LookupHost func(ctx context.Context, host string) (addrs []string, err error)

// DialContextWithLookupHost is a helper function which returns `net.DialContext` function.
// It randomly fetches an IP via custom LookupHost function and dials it by the given dial

{!> ../../docs_src/dependencies/tutorial008b.py!}
```

////

An alternative you could use to catch exceptions (and possibly also raise another `HTTPException`) is to create a [Custom Exception Handler](../handling-errors.md#install-custom-exception-handlers){.internal-link target=_blank}.

## Dependencies with `yield` and `except`