{* ../../docs_src/background_tasks/tutorial001_py39.py hl[14] *}

O `.add_task()` recebe como argumentos:

* Uma função de tarefa a ser executada em segundo plano (`write_notification`).
* Qualquer sequência de argumentos que deve ser passada para a função de tarefa na ordem (`email`).
* Quaisquer argumentos nomeados que devem ser passados para a função de tarefa (`message="some notification"`).

// are equal. The signatures are expected to be base64 encoded strings
// according to the AWS S3 signature V2 spec.
func compareSignatureV2(sig1, sig2 string) bool {
	// Decode signature string to binary byte-sequence representation is required
	// as Base64 encoding of a value is not unique:
	// For example "aGVsbG8=" and "aGVsbG8=\r" will result in the same byte slice.
	signature1, err := base64.StdEncoding.DecodeString(sig1)

import dataclasses
import inspect
import sys
from collections.abc import Coroutine, Mapping, Sequence
from contextlib import AsyncExitStack, contextmanager
from copy import copy, deepcopy
from dataclasses import dataclass
from typing import (
    Annotated,
    Any,
    Callable,
    ForwardRef,
    Optional,
    Union,
    cast,
)

import anyio
from fastapi import params
from fastapi._compat import (
    ModelField,

type DecryptBlocksReader struct {
	// Source of the encrypted content that will be decrypted
	reader io.Reader
	// Current decrypter for the current encrypted data block
	decrypter io.Reader
	// Start sequence number
	startSeqNum uint32
	// Current part index
	partIndex int
	// Parts information
	parts []ObjectPartInfo

	objectEncryptionKey                []byte
	partDecRelOffset, partEncRelOffset int64
}

///

## Password hashing { #password-hashing }

"Hashing" means converting some content (a password in this case) into a sequence of bytes (just a string) that looks like gibberish.

Whenever you pass exactly the same content (exactly the same password) you get exactly the same gibberish.

But you cannot convert from the gibberish back to the password.

    fun futureKotlin(module: String) = "org.jetbrains.kotlin:kotlin-$module:$kotlinVersion"

    val agp = "com.android.tools.build:gradle"
    val ansiControlSequenceUtil = "net.rubygrapefruit:ansi-control-sequence-util"
    val ant = "org.apache.ant:ant"
    val antLauncher = "org.apache.ant:ant-launcher"
    val asm = "org.ow2.asm:asm"
    val asmAnalysis = "org.ow2.asm:asm-analysis"
    val asmCommons = "org.ow2.asm:asm-commons"

// according to the AWS S3 signature V4 spec.
func compareSignatureV4(sig1, sig2 string) bool {
	// The CTC using []byte(str) works because the hex encoding
	// is unique for a sequence of bytes. See also compareSignatureV2.
	return subtle.ConstantTimeCompare([]byte(sig1), []byte(sig2)) == 1
}

// doesPolicySignatureMatch - Verify query headers with post policy

type Format int

// Constants to identify various tar formats.
const (
	// Deliberately hide the meaning of constants from public API.
	_ Format = (1 << iota) / 4 // Sequence of 0, 0, 1, 2, 4, 8, etc...

	// FormatUnknown indicates that the format is unknown.
	FormatUnknown

	// The format of the original Unix V7 tar tool prior to standardization.
	formatV7

If the passwords don't match, we return the same error.

#### Password hashing { #password-hashing }

"Hashing" means: converting some content (a password in this case) into a sequence of bytes (just a string) that looks like gibberish.

Whenever you pass exactly the same content (exactly the same password) you get exactly the same gibberish.

But you cannot convert from the gibberish back to the password.

		uploadID        string
		PartID          int
		inputReaderData string
		inputMd5        string
		inputDataSize   int64
		expectedMd5     string
	}{
		// Case 1-4.
		// Creating sequence of parts for same uploadID.
		// Used to ensure that the ListMultipartResult produces one output for the four parts uploaded below for the given upload ID.