```Python hl_lines="1  4"
{!../../docs_src/python_types/tutorial009.py!}
```

Door `Optional[str]` te gebruiken in plaats van alleen `str`, kan de editor je helpen fouten te detecteren waarbij je ervan uit zou kunnen gaan dat een waarde altijd een `str` is, terwijl het in werkelijkheid ook `None` zou kunnen zijn.

`Optional[EenType]` is eigenlijk een snelkoppeling voor `Union[EenType, None]`, ze zijn equivalent.

  EXPECT_EQ(0, TF_OperationGetControlInputs(neg, control_ops, 100));
  EXPECT_EQ(0, TF_OperationNumControlOutputs(neg));
  EXPECT_EQ(0, TF_OperationGetControlOutputs(neg, control_ops, 100));

  // Import it again, with an input mapping, return outputs, and a return
  // operation, into the same graph.
  TF_DeleteImportGraphDefOptions(opts);
  opts = TF_NewImportGraphDefOptions();
  TF_ImportGraphDefOptionsSetPrefix(opts, "imported2");

// The restore operation could be in one of the following states,
// - in progress (no content on MinIO's disks yet)
// - completed
// - completed but expired (again, no content on MinIO's disks)
func (r restoreObjStatus) OnDisk() bool {
	if expiry, ok := r.Expiry(); ok && time.Now().UTC().Before(expiry) {
		// completed
		return true
	}

				} else {
					hdr.Typeflag = TypeReg
				}
			}

			// The extended headers may have updated the size.
			// Thus, setup the regFileReader again after merging PAX headers.
			if err := tr.handleRegularFile(hdr); err != nil {
				return nil, err
			}

			// Sparse formats rely on being able to read from the logical data

        // empty instance already generated
        if (emptyInstanceGenerated.get(type.getType()).intValue() == freshness.get()) {
          // same freshness, generate again.
          return invokeGeneratorMethod(emptyGenerate);
        } else {
          // Cannot use empty generator. Proceed with other generators.
        }
      } else {

                  // transitioned to a failed state, also this means that shutDown has already
                  // been called, so we do not want to call it again.
                  return;
                }
                shutDown();
              } finally {
                lock.unlock();
              }
              notifyStopped();

    assertTrue("Heap is not intact after remove", mmHeap.isIntact());
    assertEquals((Integer) 10, it.next());
    assertEquals((Integer) 3, it.next());
    it.remove();
    // After this remove, 400 moved down again and 500 up past the cursor
    assertTrue("Heap is not intact after remove", mmHeap.isIntact());
    assertEquals((Integer) 12, it.next());
    assertEquals((Integer) 30, it.next());
    assertEquals((Integer) 40, it.next());

 *  New: `OkHttpClient.x509TrustManager` accessor.
 *  New: Permit [new WebSocket response codes][iana_websocket]: 1012 (Service Restart), 1013 (Try
    Again Later), and 1014 (invalid response from the upstream).
 *  New: Build with Kotlin 1.3.41, BouncyCastle 1.62, and Conscrypt 2.2.1.
 *  Fix: Recover gracefully when a coalesced connection immediately goes unhealthy.

		return cycles == 1
	}
	return uint32(xxhash.Sum64String(string(h))>>32)%(cycles) == cycle%cycles
}

// addChild will add a child based on its hash.
// If it already exists it will not be added again.
func (e *dataUsageEntry) addChild(hash dataUsageHash) {
	if _, ok := e.Children[hash.Key()]; ok {
		return
	}
	if e.Children == nil {
		e.Children = make(dataUsageHashMap, 1)
	}

 * <tr><td ><code>smb1://</code></td><td>
 * Just as <code>smb1://server/</code> lists shares and
 * <code>smb1://workgroup/</code> lists servers, the <code>smb1://</code>
 * URL lists all available workgroups on a netbios LAN. Again,
 * in this context many methods are not valid and return default
 * values(e.g. <code>isHidden</code> will always return false).
 * </td></tr>
 *