## In a hurry?

<abbr title="too long; didn't read"><strong>TL;DR:</strong></abbr>

If you are using third party libraries that tell you to call them with `await`, like:

```Python
results = await some_library()
```

Then, declare your *path operation functions* with `async def` like:

```Python hl_lines="2"
@app.get('/')
async def read_results():
    results = await some_library()
    return results
```

!!! note

## Multiple body parameters

In the previous example, the *path operations* would expect a JSON body with the attributes of an `Item`, like:

```JSON
{
    "name": "Foo",
    "description": "The pretender",
    "price": 42.0,
    "tax": 3.2
}
```

But you can also declare multiple body parameters, e.g. `item` and `user`:

	Operand  *Operand `parser:"  @@"`
}

// Like represents the RHS of a LIKE expression
type Like struct {
	Not        bool     `parser:" @\"NOT\"? "`
	Pattern    *Operand `parser:" \"LIKE\" @@ "`
	EscapeChar *Operand `parser:" (\"ESCAPE\" @@)? "`
}

// Between represents the RHS of a BETWEEN expression
type Between struct {

  }

  fun assertRequests(vararg expectedHosts: String?) {
    assertThat(requestedHosts).containsExactly(*expectedHosts)
    requestedHosts.clear()
  }

  /** Allocates and returns `count` fake IPv4 addresses like [255.0.0.100, 255.0.0.101].  */
  fun allocate(count: Int): List<InetAddress> {
    val from = nextAddress
    nextAddress += count
    return (from until nextAddress)
      .map {

        assertEquals(UserAgentType.IE, userAgentHelper.getUserAgentType());
    }

    public void test_getUserAgentType_Chrome() {
        getMockRequest().addHeader("user-agent",
                "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/28.0.1500.52 Safari/537.36");

    return result
  }
}

internal data class AlgorithmIdentifier(
  /** An OID string like "1.2.840.113549.1.1.11" for sha256WithRSAEncryption. */
  val algorithm: String,
  /** Parameters of a type implied by [algorithm]. */
  val parameters: Any?,
)

internal data class AttributeTypeAndValue(
  /** An OID string like "2.5.4.11" for organizationalUnitName. */
  val type: String,
  val value: Any?,
)

		result.combine(e.Between.Start.analyze(s))
		result.combine(e.Between.End.analyze(s))
	case e.In != nil:
		result.combine(e.In.analyze(s))
	case e.Like != nil:
		result.combine(e.Like.Pattern.analyze(s))
		if e.Like.EscapeChar != nil {
			result.combine(e.Like.EscapeChar.analyze(s))
		}
	default:
		result = qProp{err: errUnexpectedInvalidNode}
	}
	return
}

```console
$ pip install websockets

---> 100%
```

</div>

## WebSockets client

### In production

In your production system, you probably have a frontend created with a modern framework like React, Vue.js or Angular.

And to communicate using WebSockets with your backend you would probably use your frontend's utilities.

 *  Fix: Use literal IP addresses directly rather than passing them to `DnsOverHttps`.
 *  Fix: Embed Proguard rules to prevent warnings from tools like DexGuard and R8. These warnings
    were triggered by OkHttp’s feature detection for TLS packages like `org.conscrypt`,
    `org.bouncycastle`, and `org.openjsse`.
 *  Upgrade: Explicitly depend on `kotlin-stdlib-jdk8`. This fixes a problem with dependency

Aso, when returning several objects, like in `get_users`, we directly call `list`, like in:

```Python
list(models.User.select())
```