## What makes a dependency

Up to now you have seen dependencies declared as functions.

But that's not the only way to declare dependencies (although it would probably be the more common).

The key factor is that a dependency should be a "callable".

A "**callable**" in Python is anything that Python can "call" like a function.

// The env var no longer exists afterwards
$ python main.py

Hello World from Python
```

</div>

!!! tip
    You can read more about it at <a href="https://12factor.net/config" class="external-link" target="_blank">The Twelve-Factor App: Config</a>.

### Types and validation

  private val routePlanner = FakeRoutePlanner()
  private val factory = routePlanner.factory
  private val taskFaker = routePlanner.taskFaker
  private val peer = MockHttp2Peer()

  /** The fake task runner prevents the cleanup runnable from being started.  */
  private val addressA = factory.newAddress("a")
  private val routeA1 = factory.newRoute(addressA)
  private val addressB = factory.newAddress("b")

import okhttp3.internal.connection.RoutePlanner
import okhttp3.internal.connection.RoutePlanner.ConnectResult

class FakeRoutePlanner(
  val factory: TestValueFactory = TestValueFactory(),
  val taskFaker: TaskFaker = factory.taskFaker,
) : RoutePlanner, Closeable {
  val pool = factory.newConnectionPool(routePlanner = this)
  val events = LinkedBlockingDeque<String>()
  var canceled = false
  var autoGeneratePlans = false

Import the `Response` class (sub-class) you want to use and declare it in the *path operation decorator*.

For large responses, returning a `Response` directly is much faster than returning a dictionary.

* **Machine Learning**: it normally requires lots of "matrix" and "vector" multiplications. Think of a huge spreadsheet with numbers and multiplying all of them together at the same time.

`tf.reverse_v2()` will remain until 1.0 final. * `tf.mul`, `tf.sub` and `tf.neg`
are deprecated in favor of `tf.multiply`, `tf.subtract` and `tf.negative`. *
`tf.pack` and `tf.unpack` are deprecated in favor of `tf.stack` and
`tf.unstack`. * `TensorArray.pack` and `TensorArray.unpack` are getting
deprecated in favor of `TensorArray.stack` and `TensorArray.unstack`. * The

`wait.NewExponentialBackoffManager` and `wait.NewJitteringBackoffManager` functions have been marked as deprecated.  Callers should switch to using the `Backoff{...}.DelayWithReset(clock, resetInterval)` method and must set the `Steps` field when using `Factor`. As a short term change, callers may use the `Timer()` method on the `BackoffManager` until the backoff managers are deprecated and removed. Please see the godoc of the deprecated functions for examples of how to replace usage of this function. ...

 *
 * This class is pretty fast and loose with default values: it attempts to provide values that are
 * well-formed, but doesn't guarantee values are internally consistent. Callers must take care to
 * configure the factory when sample values impact the correctness of the test.
 */
class TestValueFactory : Closeable {
  var taskFaker: TaskFaker = TaskFaker()
  var taskRunner: TaskRunner = taskFaker.taskRunner
  var dns: Dns = Dns.SYSTEM

}

public final class okhttp3/OkHttp {
	public static final field INSTANCE Lokhttp3/OkHttp;
	public static final field VERSION Ljava/lang/String;
}

public class okhttp3/OkHttpClient : okhttp3/Call$Factory, okhttp3/WebSocket$Factory {
	public static final field Companion Lokhttp3/OkHttpClient$Companion;
	public final fun -deprecated_authenticator ()Lokhttp3/Authenticator;
	public final fun -deprecated_cache ()Lokhttp3/Cache;