func lcpSuffix(strs []string) string {
	return lcp(strs, false)
}

func lcp(strs []string, pre bool) string {
	// short-circuit empty list
	if len(strs) == 0 {
		return ""
	}
	xfix := strs[0]
	// short-circuit single-element list
	if len(strs) == 1 {
		return xfix
	}
	// compare first to rest
	for _, str := range strs[1:] {
		xfixl := len(xfix)
		strl := len(str)

}

// Get the server port from server.URL (e.g., https://127.0.0.1:36253)
func getServerPort(server *httptest.Server) (int, error) {
	strs := strings.Split(server.URL, ":")
	if len(strs) < 2 {
		return 0, fmt.Errorf("server.URL is invalid: %v", server.URL)
	}
	port, err := strconv.Atoi(strs[len(strs)-1])
	if err != nil {
		return 0, fmt.Errorf("error to extract port from URL: %v", server.URL)
	}
	return port, nil
}

    ```

The query parameter `q` is of type `Union[str, None]` (or `str | None` in Python 3.10), that means that it's of type `str` but could also be `None`, and indeed, the default value is `None`, so FastAPI will know it's not required.

!!! note
    FastAPI will know that the value of `q` is not required because of the default value `= None`.

	Bo bool `json:"bo,omitempty"`

	Ur uint `json:"ur"`
	Uo uint `json:"uo,omitempty"`

	Str struct{} `json:"str"`
	Sto struct{} `json:"sto,omitempty"`
}

func TestOmitEmpty(t *testing.T) {
	var want = `{
 "sr": "",
 "omitempty": 0,
 "slr": null,
 "mr": {},
 "fr": 0,
 "br": false,
 "ur": 0,
 "str": {},
 "sto": {}
}`
	var o Optionals
	o.Sw = "something"
	o.Mr = map[string]any{}

	NumUnit map[string][]string

	locationIDX []uint64
	labelX      []label
}

// label corresponds to Profile.Label
type label struct {
	keyX int64
	// Exactly one of the two following values must be set
	strX int64
	numX int64 // Integer value for this label
	// can be set if numX has value
	unitX int64
}

// Mapping corresponds to Profile.Mapping
type Mapping struct {
	ID              uint64