The **TLS certificates** are **associated with a domain name**, not with an IP address.

So, to renew the certificates, the renewal program needs to **prove** to the authority (Let's Encrypt) that it indeed **"owns" and controls that domain**.

To do that, and to accommodate different application needs, there are several ways it can do it. Some popular ways are:

* **Modify some DNS records**.

    assertThat(networkString).contains("allowsSelfLoops: " + network.allowsSelfLoops());

    int nodeStart = networkString.indexOf("nodes:");
    int edgeStart = networkString.indexOf("edges:");
    String nodeString = networkString.substring(nodeStart, edgeStart);
    String edgeString = networkString.substring(edgeStart);

    Graph<N> asGraph = network.asGraph();

    // Extract the regular sequence of routes from selector.
    val selection1 = routeSelector.next()
    val regularRoutes = selection1.routes

    // Check that we do indeed have more than one route.
    assertThat(regularRoutes.size).isEqualTo(numberOfAddresses)
    // Add first regular route as failed.
    routeDatabase.failed(regularRoutes[0])
    // Reset selector

index-01-swagger-ui-simple.png...

![Swagger UI](https://fastapi.tiangolo.com/img/index/index-03-swagger-02.png)

* Click on the button "Try it out", it allows you to fill the parameters and directly interact with the API:

![Swagger UI interaction](https://fastapi.tiangolo.com/img/index/index-04-swagger-03.png)

    }

    private int reverseIndex(int index) {
      int size = size();
      checkElementIndex(index, size);
      return (size - 1) - index;
    }

    private int reversePosition(int index) {
      int size = size();
      checkPositionIndex(index, size);
      return size - index;
    }

    @Override
    public void add(int index, @ParametricNullness T element) {

    assertEquals(1, Iterators.indexOf(iterator, equalTo("mo")));
    assertEquals("jack", iterator.next());
    assertFalse(iterator.hasNext());
  }

  public void testIndexOf_consumedDataWithDuplicates() {
    Iterator<String> iterator = Lists.newArrayList("manny", "mo", "mo", "jack").iterator();
    assertEquals(1, Iterators.indexOf(iterator, equalTo("mo")));
    assertEquals("mo", iterator.next());

  /**
   * Returns the stripe at the specified index. Valid indexes are 0, inclusively, to {@code size()},
   * exclusively.
   *
   * @param index the index of the stripe to return; must be in {@code [0...size())}
   * @return the stripe at the specified index
   */
  public abstract L getAt(int index);

  /**
   * Returns the index to which the given key is mapped, so that getAt(indexFor(key)) == get(key).

        /*
         * try { ArtifactResolutionResult res = collect( a ); fail( "Expected b not to resolve: " + res ); } catch (
         * OverConstrainedVersionException e ) { assertTrue( e.getMessage().indexOf( "[1.0-SNAPSHOT]" ) <
         * e.getMessage().indexOf( "[1.0,)" ) ); }
         */
    }

    @Test
    @Disabled("that one does not work")
    void testOverConstrainedVersionException()

        list.addLast("1");
        list.addLast("2");
        list.addLast("3");
        assertThat(list.indexOf(null), is(0));
        assertThat(list.indexOf("1"), is(1));
        assertThat(list.indexOf("2"), is(2));
        assertThat(list.indexOf("3"), is(3));
        assertThat(list.indexOf("4"), is(-1));
    }