Entonces, si tienes un objeto `something` (que podría _no_ ser una función) y puedes "llamarlo" (ejecutarlo) como:

```Python
something()
```

o

```Python
something(some_argument, some_keyword_argument="foo")
```

entonces es un "callable".

## Clases como dependencias { #classes-as-dependencies_1 }

Puedes notar que para crear una instance de una clase en Python, utilizas esa misma sintaxis.

		EventName:  eventName,
		BucketName: bucket,
		Object:     objInfo,
		UserAgent:  "Internal: [Replication]",
		Host:       globalLocalNodeName,
	})

	// re-queue failures once more - keep a retry count to avoid flooding the queue if
	// the target site is down. Leave it to scanner to catch up instead.
	if rinfos.ReplicationStatus() != replication.Completed {
		ri.OpType = replication.HealReplicationType

Cuando instalas FastAPI, viene con un servidor de producción, Uvicorn, y puedes iniciarlo con el comando `fastapi run`.

Pero también puedes instalar un servidor ASGI manualmente.

Asegúrate de crear un [entorno virtual](../virtual-environments.md), actívalo, y luego puedes instalar la aplicación del servidor.

Por ejemplo, para instalar Uvicorn:

<div class="termy">

```console

import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.CollectionSize;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests {@code poll()} operations on a queue. Can't be invoked directly;
 * please see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
 *
 * @author Jared Levy
 */
@GwtCompatible

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.features.CollectionFeature;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests offer operations on a queue. Can't be invoked directly; please
 * see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
 *
 * @author Jared Levy
 */
@GwtCompatible

### Concurrencia + Paralelismo: Web + Machine Learning { #concurrency-parallelism-web-machine-learning }

Con **FastAPI** puedes aprovechar la concurrencia que es muy común para el desarrollo web (la misma atracción principal de NodeJS).

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.features.CollectionFeature;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests offer operations on a queue. Can't be invoked directly; please
 * see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
 *
 * @author Jared Levy
 */
@GwtCompatible

import com.google.common.collect.testing.features.CollectionSize;
import java.util.NoSuchElementException;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests {@code element()} operations on a queue. Can't be invoked
 * directly; please see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
 *
 * @author Jared Levy
 */
@GwtCompatible

import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.CollectionSize;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests {@code peek()} operations on a queue. Can't be invoked directly;
 * please see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
 *
 * @author Jared Levy
 */
@GwtCompatible

    /** Atomic flag indicating whether the crawler is currently running. */
    private static AtomicBoolean running = new AtomicBoolean(false);

    /** Thread-safe queue for collecting error messages during crawling operations. */
    private static Queue<String> errors = new ConcurrentLinkedQueue<>();

    /** Injected search engine client for OpenSearch operations. */
    @Resource