assertRoute(selection.next(), address, Proxy.NO_PROXY, dns.lookup(uriHost, 0), uriPort)
    assertThat(selection.hasNext()).isFalse()
    assertFailsWith<NoSuchElementException> {
      selection.next()
    }
    assertThat(routeSelector.hasNext()).isFalse()
    assertFailsWith<NoSuchElementException> {
      routeSelector.next()
    }
  }

  @Test fun explicitProxyTriesThatProxysAddressesOnly() {
    val address =

    if (!newRouteSelector.hasNext()) throw IOException("exhausted all routes")
    val newRouteSelection = newRouteSelector.next()
    routeSelection = newRouteSelection

    if (isCanceled()) throw IOException("Canceled")

    return planConnectToRoute(newRouteSelection.next(), newRouteSelection.routes)
  }

  /**
   * Returns a plan to reuse a pooled connection, or null if the pool doesn't have a connection for

): List<T> {
  val ia = a.iterator()
  val ib = b.iterator()

  return buildList {
    while (ia.hasNext() || ib.hasNext()) {
      if (ia.hasNext()) {
        add(ia.next())
      }
      if (ib.hasNext()) {
        add(ib.next())
      }
    }
  }
}

// TODO check read only options for creating lists
public fun <T> List<T>.readOnly() = this.toList()

        }

        return false
      }

      override fun next(): String {
        if (!hasNext()) throw NoSuchElementException()
        val result = nextUrl!!
        nextUrl = null
        canRemove = true
        return result
      }

      override fun remove() {
        check(canRemove) { "remove() before next()" }
        delegate.remove()
      }
    }
  }

I'll show you some concrete examples in the next chapters.

---

Then the next concepts to consider are all about the program running your actual API (e.g. Uvicorn).

## Program and Process

 *    we must send a `CONNECT` request, and handle authorization challenges from the proxy.
 *  * Optional [TLS handshake][connectTls].
 *
 * Each step may fail. If a retry is possible, a new instance is created with the next plan, which
 * will be configured differently.
 */
class ConnectPlan(
  private val taskRunner: TaskRunner,
  private val connectionPool: RealConnectionPool,
  private val readTimeoutMillis: Int,

```Python hl_lines="18-20"
{!../../../docs_src/sql_databases_peewee/sql_app/main.py!}
```

For the **next request**, as we will reset that context variable again in the `async` dependency `reset_db_state()` and then create a new connection in the `get_db()` dependency, that new request will have its own database state (connection, transactions, etc).

        ":tf_buffer_internal",
        ":tf_status",
        ":tf_status_helper",
        ":tf_tensor_internal",
        "//tensorflow/core/common_runtime/next_pluggable_device/c:tf_rendezvous_c_api",
        "//tensorflow/core/common_runtime/next_pluggable_device/c:tf_rendezvous_c_api_internal",
        "//tensorflow/core/platform:notification",
        "@com_google_absl//absl/status",
        "@com_google_absl//absl/strings",

          if (closed) return false

          while (delegate.hasNext()) {
            nextSnapshot = delegate.next()?.snapshot() ?: continue
            return true
          }
        }

        return false
      }

      override fun next(): Snapshot {
        if (!hasNext()) throw NoSuchElementException()
        removeSnapshot = nextSnapshot
        nextSnapshot = null

And it should have an `access_token`, with a string containing our access token.

For this simple example, we are going to just be completely insecure and return the same `username` as the token.

!!! tip
    In the next chapter, you will see a real secure implementation, with password hashing and <abbr title="JSON Web Tokens">JWT</abbr> tokens.

    But for now, let's focus on the specific details we need.

=== "Python 3.10+"