normal para una pequeña ganancia de rendimiento (alrededor de 100 nanosegundos), ten en cuenta que en **FastAPI** el efecto sería bastante opuesto. En estos casos, es mejor usar `async def` a menos que tus *path operation functions* usen código que realice <abbr title="Input/Output: lectura o escritura en disco, comunicaciones de red.">I/O</abbr> de bloqueo.

Aun así, en ambas situaciones, es probable que **FastAPI** [siga siendo más rápida](index.md#performance){.internal-link target=_blank}...

// of the line. The returned buffer is only valid until the next call to
// ReadLine. ReadLine either returns a non-nil line or it returns an error,
// never both.
//
// The text returned from ReadLine does not include the line end ("\r\n" or "\n").
// No indication or error is given if the input ends without a final line end.
// Calling [Reader.UnreadByte] after ReadLine will always unread the last byte read

        }
        return result;
    }

    static void populate(final Reader r) throws IOException {
        String line;
        final BufferedReader br = new BufferedReader(r);

        while ((line = br.readLine()) != null) {
            line = line.toUpperCase().trim();
            if (line.length() == 0) {
                continue;
            }
            if (line.charAt(0) == '#') {

        return result;
    }

    void populate(final Reader r, final CIFSContext tc) throws IOException {
        String line;
        final BufferedReader br = new BufferedReader(r);

        while ((line = br.readLine()) != null) {
            line = line.toUpperCase().trim();
            if (line.length() == 0) {
                continue;
            }
            if (line.charAt(0) == '#') {

    val reader = BufferedReader(InputStreamReader(connection.inputStream, UTF_8))
    assertThat(connection.responseCode).isEqualTo(HttpURLConnection.HTTP_OK)
    assertThat(reader.readLine()).isEqualTo("hello world")
    val request = server.takeRequest()
    assertThat(request.requestLine).isEqualTo("GET / HTTP/1.1")
    assertThat(request.headers["Accept-Language"]).isEqualTo("en-US")

                        result = result.replace("${" + key + "}", String.valueOf(value));
                    } else if (value instanceof TestUser) {
                        // Handle TestUser object
                        TestUser user = (TestUser) value;
                        result = result.replace("${" + key + ".name}", user.name);
                        result = result.replace("${" + key + ".age}", String.valueOf(user.age));

    val reader = BufferedReader(InputStreamReader(inputStream, StandardCharsets.UTF_8))
    assertThat(connection.getResponseCode()).isEqualTo(HttpURLConnection.HTTP_OK)
    assertThat(reader.readLine()).isEqualTo("hello world")
    val request = server.takeRequest()
    assertThat(request.requestLine).isEqualTo("GET / HTTP/1.1")
    assertThat(request.getHeader("Accept-Language")).isEqualTo("en-US")

        assertArgumentNotNull("reader", reader);
        this.reader = reader;
    }

    @Override
    public boolean hasNext() {
        if (line == EMPTY) {
            line = ReaderUtil.readLine(reader);
        }
        return line != null;
    }

    @Override
    public String next() {
        if (!hasNext()) {
            throw new NoSuchElementException();
        }

So, in our example, we can make `tags` be specifically a "list of strings":

{* ../../docs_src/body_nested_models/tutorial002_py310.py hl[12] *}

## Set types { #set-types }

But then we think about it, and realize that tags shouldn't repeat, they would probably be unique strings.

And Python has a special data type for sets of unique items, the `set`.

Then we can declare `tags` as a set of strings:

		t.Fatalf("Preload many2many relations")
	}

	// Replace
	tag5 := &Tag{Locale: "ZH", Value: "tag5"}
	tag6 := &Tag{Locale: "ZH", Value: "tag6"}
	DB.Model(&blog).Association("Tags").Replace(tag5, tag6)
	var tags2 []Tag
	DB.Model(&blog).Association("Tags").Find(&tags2)
	if !compareTags(tags2, []string{"tag5", "tag6"}) {
		t.Fatalf("Should find 2 tags after Replace")
	}

	if DB.Model(&blog).Association("Tags").Count() != 2 {