And dependencies can be created in a very simple and intuitive way that allows you to just import the Python packages you need, and integrate them with your API functions in a couple of lines of code, *literally*.

You will see examples of this in the next chapters, about relational and NoSQL databases, security, etc.

## **FastAPI** compatibility

func setPutObjHeaders(w http.ResponseWriter, objInfo ObjectInfo, delete bool, h http.Header) {
	// We must not use the http.Header().Set method here because some (broken)
	// clients expect the ETag header key to be literally "ETag" - not "Etag" (case-sensitive).
	// Therefore, we have to set the ETag directly as map entry.
	if objInfo.ETag != "" && !delete {
		w.Header()[xhttp.ETag] = []string{`"` + objInfo.ETag + `"`}
	}

// record is formatted as:
//
//	"%d %s=%s\n" % (size, key, value)
//
// Keys and values should be UTF-8, but the number of bad writers out there
// forces us to be a more liberal.
// Thus, we only reject all keys with NUL, and only reject NULs in values
// for the PAX version of the USTAR string fields.
// The key must not contain an '=' character.
func validPAXRecord(k, v string) bool {

// http.Header.Set(...). Otherwise, some S3 clients will not
// able to extract the ETag.
func Set(etag ETag, h http.Header) {
	// Some (broken) S3 clients expect the ETag header to
	// literally "ETag" - not "Etag". Further, some clients
	// expect an ETag in double quotes. Therefore, we set the
	// ETag directly as map entry instead of using http.Header.Set
	h["ETag"] = []string{`"` + etag.String() + `"`}
}

---------- Instead of having this chart create the secret for you, you can supply a preexisting secret, much like an existing PersistentVolumeClai. First, create the secret: ```bash kubectl create secret generic my-minio-secret --from-literal=rootUser=foobarbaz --from-literal=rootPassword=foobarbazqux ``` Then install the chart, specifying that you want to use an existing secret: ```bash helm install --set existingSecret=my-minio-secret minio/minio ``` The following fields are expected in the secret: |...

   */
  static @Nullable Object[] toArrayImpl(Collection<?> c) {
    return fillArray(c, new Object[c.size()]);
  }

  /**
   * Returns a copy of the specified subrange of the specified array that is literally an Object[],
   * and not e.g. a {@code String[]}.
   */
  static @Nullable Object[] copyAsObjectArray(@Nullable Object[] elements, int offset, int length) {

---------- Instead of having this chart create the secret for you, you can supply a preexisting secret, much like an existing PersistentVolumeClai. First, create the secret: ```bash kubectl create secret generic my-minio-secret --from-literal=rootUser=foobarbaz --from-literal=rootPassword=foobarbazqux ``` Then install the chart, specifying that you want to use an existing secret: ```bash helm install --set existingSecret=my-minio-secret minio/minio ``` The following fields are expected in the secret: |...

---------- Instead of having this chart create the secret for you, you can supply a preexisting secret, much like an existing PersistentVolumeClai. First, create the secret: ```bash kubectl create secret generic my-minio-secret --from-literal=rootUser=foobarbaz --from-literal=rootPassword=foobarbazqux ``` Then install the chart, specifying that you want to use an existing secret: ```bash helm install --set existingSecret=my-minio-secret minio/minio ``` The following fields are expected in the secret: |...

Still, probably better to use the `Annotated` version. 😉

///

////

### Required with Ellipsis (`...`)

There's an alternative way to explicitly declare that a value is required. You can set the default to the literal value `...`:

//// tab | Python 3.9+

```Python hl_lines="9"
{!> ../../docs_src/query_params_str_validations/tutorial006b_an_py39.py!}
```

////

//// tab | Python 3.8+

//	String: the number of bytes in v.
//	Channel: the number of elements queued (unread) in the channel buffer;
//	         if v is nil, len(v) is zero.
//
// For some arguments, such as a string literal or a simple array expression, the
// result can be a constant. See the Go language specification's "Length and
// capacity" section for details.
func len(v Type) int