`UploadFile` has the following `async` methods. They all call the corresponding file methods underneath (using the internal `SpooledTemporaryFile`).

* `write(data)`: Writes `data` (`str` or `bytes`) to the file.
* `read(size)`: Reads `size` (`int`) bytes/characters of the file.

Because of that, it's now recommended to instead use the `lifespan` as explained above.

## Technical Details { #technical-details }

Just a technical detail for the curious nerds. 🤓

Underneath, in the ASGI technical specification, this is part of the <a href="https://asgi.readthedocs.io/en/latest/specs/lifespan.html" class="external-link" target="_blank">Lifespan Protocol</a>, and it defines events called `startup` and `shutdown`.

Import `SQLModel` and create a database model:

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[1:11] hl[7:11] *}

The `Hero` class is very similar to a Pydantic model (in fact, underneath, it actually *is a Pydantic model*).

There are a few differences:

		return nil, err
	}

	return &sarama.ProducerMessage{
		Topic: target.args.Topic,
		Key:   sarama.StringEncoder(key),
		Value: sarama.ByteEncoder(data),
	}, nil
}

// Close - closes underneath kafka connection.
func (target *KafkaTarget) Close() error {
	close(target.quitCh)

	if target.batch != nil {
		target.batch.Close()
	}

	if target.producer != nil {
		if target.store != nil {

		if IsConnErr(err) {
			return store.ErrNotConnected
		}
		return err
	}

	// Delete the event from store.
	return target.store.Del(key)
}

// Close - closes underneath connections to MySQL database.
func (target *MySQLTarget) Close() error {
	close(target.quitCh)
	if target.updateStmt != nil {
		// FIXME: log returned error. ignore time being.
		_ = target.updateStmt.Close()
	}

		if IsConnErr(err) {
			return store.ErrNotConnected
		}
		return err
	}

	// Delete the event from store.
	return target.store.Del(key)
}

// Close - closes underneath connections to PostgreSQL database.
func (target *PostgreSQLTarget) Close() error {
	close(target.quitCh)
	if target.updateStmt != nil {
		// FIXME: log returned error. ignore time being.

		if os.IsNotExist(eErr) {
			return nil
		}
		return eErr
	}

	if err := target.send(eventData); err != nil {
		return err
	}

	return target.store.Del(key)
}

// Close - closes underneath connections to NATS server.
func (target *NATSTarget) Close() (err error) {
	close(target.quitCh)
	if target.stanConn != nil {
		// closing the streaming connection does not close the provided NATS connection.

In the chapters about security, there are utility functions that are implemented in this same way.

If you understood all this, you already know how those utility tools for security work underneath.

///

## Dependencies with `yield`, `HTTPException`, `except` and Background Tasks { #dependencies-with-yield-httpexception-except-and-background-tasks }

/// warning

**In our tests we also found ext4 does not honor POSIX O_DIRECT/Fdatasync semantics, ext4 trades performance for consistency guarantees. Please avoid ext4 in your setup.**

**If MinIO distributed setup is using NFS volumes underneath it is not guaranteed MinIO will provide these consistency guarantees since NFS is not strictly consistent (If you must use NFS we recommend that you at least use NFSv4 instead of NFSv3 for relatively better outcomes).**

## Get started

$ python main.py

I solemnly swear 🐺
```

</div>

## Alternatives { #alternatives }

This is a simple guide to get you started and teach you how everything works **underneath**.

There are many **alternatives** to managing virtual environments, package dependencies (requirements), projects.