for input.Scan() {
		line := strings.TrimSpace(input.Text())
		if line == "" {
			continue
		}
		// Find first separator.
		idx := strings.IndexByte(line, trailerKVSeparator[0])
		if idx <= 0 || idx >= len(line) {
			if cr.debug {
				fmt.Printf("Could not find separator, got %q\n", line)
			}
			return errMalformedEncoding
		}
		key := strings.ToLower(line[:idx])
		value := line[idx+1:]

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: float = 10.5
    tags: list[str] = []


items = {
    "foo": {"name": "Foo", "price": 50.2},
    "bar": {"name": "Bar", "description": "The bartenders", "price": 62, "tax": 20.2},
    "baz": {"name": "Baz", "description": None, "price": 50.2, "tax": 10.5, "tags": []},
}

```

////

В обоих случаях это означает, что `item` может быть `int` или `str`.

#### Возможно `None` { #possibly-none }

Вы можете объявить, что значение может иметь определённый тип, например `str`, но также может быть и `None`.

В Python 3.6 и выше (включая Python 3.10) это можно объявить, импортировав и используя `Optional` из модуля `typing`.

```Python hl_lines="1  4"

                """
            ),
        ] = None,
        description: Annotated[
            Optional[str],
            Doc(
                """
                Security scheme description.

                It will be included in the generated OpenAPI (e.g. visible at `/docs`).
                """
            ),
        ] = None,
        auto_error: Annotated[
            bool,
            Doc(

def say_hi(name: str | None = None):
    if name is not None:
        print(f"Hey {name}!")
    else:

   * '\n'}), a carriage return ({@code '\r'}), or a carriage return followed immediately by a
   * linefeed ({@code "\r\n"}).
   *
   * @return a {@code String} containing the contents of the line, not including any
   *     line-termination characters, or {@code null} if the end of the stream has been reached.
   * @throws IOException if an I/O error occurs
   */
  @CanIgnoreReturnValue // to skip a line

		for i := range erasureDisks[:8] {
			erasureDisks[i] = nil
		}
		return erasureDisks
	}
	z.serverPools[0].erasureDisksMu.Unlock()

	t.Run("if-none-match with read quorum failure", func(t *testing.T) {
		// Test Case 1: if-none-match (create only if doesn't exist)
		// With if-none-match: *, this should only succeed if object doesn't exist.
		// Since read quorum fails, we can't determine if object exists.
		opts := ObjectOptions{

# Treat all files in the Go repo as binary, with no git magic updating
# line endings. This produces predictable results in different environments.
#
# Windows users contributing to Go will need to use a modern version
# of git and editors capable of LF line endings.
#
# Windows .bat files are known to have multiple bugs when run with LF
# endings, and so they are checked in with CRLF endings, with a test

from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: Union[int, None] = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: Union[int, None] = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

	}
	data = data[len(line):]
	line, isPrefix, err = l.ReadLine()
	if isPrefix || !bytes.Equal(line, data[:minReadBufferSize/2]) || err != nil {
		t.Errorf("bad result for third line: got %q want %q %v", line, data[:minReadBufferSize/2], err)
	}
	line, isPrefix, err = l.ReadLine()
	if isPrefix || err == nil {
		t.Errorf("expected no more lines: %x %s", line, err)
	}
}