// not be required but makes reproduction much easier.
		nsLk.lockMapMutex.Lock()

		// lk3 blocks.
		lk3ch := make(chan bool)
		go func() {
			lk3ch <- nsLk.lock(ctx, "volume", "path", "source", "opsID", false, 0)
		}()

		// lk4, blocks.
		lk4ch := make(chan bool)
		go func() {
			lk4ch <- nsLk.lock(ctx, "volume", "path", "source", "opsID", false, 0)

If there's a security flaw in your code, it will still exist.

        } else {
          continue; // delete this entry; we already copied an earlier one for the same key
        }
      }
      newEntries[out++] = entry;
    }
    return newEntries;
  }

  /** Makes an entry usable internally by a new ImmutableMap without rereading its contents. */
  static <K, V> ImmutableMapEntry<K, V> makeImmutable(Entry<K, V> entry, K key, V value) {
    boolean reusable =

But I'll show you how to improve that next. 🤓

## Custom Operation IDs and Better Method Names { #custom-operation-ids-and-better-method-names }

You can **modify** the way these operation IDs are **generated** to make them simpler and have **simpler method names** in the clients.

In the same way, you can use `finally` to make sure the exit steps are executed, no matter if there was an exception or not.

{* ../../docs_src/dependencies/tutorial007.py hl[3,5] *}

## Sub-dependencies with `yield` { #sub-dependencies-with-yield }

You can have sub-dependencies and "trees" of sub-dependencies of any size and shape, and any or all of them can use `yield`.

`OAuth2PasswordBearer` makes **FastAPI** know that it is a security scheme. So it is added that way to OpenAPI.

But `OAuth2PasswordRequestForm` is just a class dependency that you could have written yourself, or you could have declared `Form` parameters directly.

But as it's a common use case, it is provided by **FastAPI** directly, just to make it easier.

///

### Use the form data { #use-the-form-data }

### Retrieving Container ID

To use Docker commands on a specific container, you need to know the `Container ID` for that container. To get the `Container ID`, run

```sh
docker ps -a
```

`-a` flag makes sure you get all the containers (Created, Running, Exited). Then identify the `Container ID` from the output.

### Starting and Stopping Containers

        assertTrue(h.isValid());

        // Tree id change makes it invalid
        when(tree.getTreeId()).thenReturn(11L);
        assertFalse(h.isValid());

        // Connected=false makes it invalid
        when(tree.getTreeId()).thenReturn(10L);
        when(tree.isConnected()).thenReturn(false);
        assertFalse(h.isValid());

        // Mark closed makes it invalid
        when(tree.isConnected()).thenReturn(true);

	return err
}

// NewTierConfigMgr - creates new tier configuration manager,
func NewTierConfigMgr() *TierConfigMgr {
	return &TierConfigMgr{
		drivercache: make(map[string]WarmBackend),
		Tiers:       make(map[string]madmin.TierConfig),
	}
}

func (config *TierConfigMgr) refreshTierConfig(ctx context.Context, objAPI ObjectLayer) {
	const tierCfgRefresh = 15 * time.Minute

> Modern versions of Python have support for **"asynchronous code"** using something called **"coroutines"**, with **`async` and `await`** syntax.

That should make more sense now. ✨

All that is what powers FastAPI (through Starlette) and what makes it have such an impressive performance.

## Very Technical Details { #very-technical-details }

/// warning

You can probably skip this.