* (IOException) e.getCause()} throws a {@link ClassCastException} that discards the original
   * exception {@code e} if the cause is not an {@link IOException}, but {@code
   * Throwables.getCauseAs(e, IOException.class)} keeps {@code e} as the {@link
   * ClassCastException}'s cause.
   *
   * @throws ClassCastException if the cause cannot be cast to the expected type. The {@code
   *     ClassCastException}'s cause is {@code throwable}.

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[21:22] hl[21:22] *}

### Create a Session Dependency { #create-a-session-dependency }

A **`Session`** is what stores the **objects in memory** and keeps track of any changes needed in the data, then it **uses the `engine`** to communicate with the database.

Those two tasks are what **consume time the most**. That's the main work of maintaining FastAPI.

If you can help me with that, **you are helping me maintain FastAPI** and making sure it keeps **advancing faster and better**. 🚀

## Join the chat { #join-the-chat }

	updateCurrentPath func(string)
}

// Cache structure and compaction:
//
// A cache structure will be kept with a tree of usages.
// The cache is a tree structure where each keeps track of its children.
//
// An uncompacted branch contains a count of the files only directly at the
// branch level, and contains link to children branches or leaves.
//

   * elements.length) are all {@code null}.
   */
  @VisibleForTesting transient @Nullable Object @Nullable [] elements;

  /**
   * Keeps track of metadata like the number of hash table bits and modifications of this data
   * structure (to make it possible to throw ConcurrentModificationException in the iterator). Note

   * values.length) are all {@code null}.
   */
  @VisibleForTesting transient @Nullable Object @Nullable [] values;

  /**
   * Keeps track of metadata like the number of hash table bits and modifications of this data
   * structure (to make it possible to throw ConcurrentModificationException in the iterator). Note

    /**
     * @return {@code true} if the current thread has acquired this lock.
     */
    boolean isAcquiredByCurrentThread();
  }

  /**
   * A {@code LockGraphNode} associated with each lock instance keeps track of the directed edges in
   * the lock acquisition graph.
   */
  private static final class LockGraphNode {

    /**

 *
 * <p><a id="iteration"></a>
 *
 * <p><b>Key-grouped iteration.</b> All view collections follow the same iteration order. In all
 * current implementations, the iteration order always keeps multiple entries with the same key
 * together. Any creation method that would customarily respect insertion order (such as {@link
 * #copyOf(Multimap)}) instead preserves key-grouped order by inserting entries for an existing key

   * but mutates {@code multisetToModify} instead of returning a view.
   *
   * <p>In contrast, {@code multisetToModify.retainAll(multisetToRetain)} keeps all occurrences of
   * elements that appear at all in {@code multisetToRetain}, and deletes all occurrences of all
   * other elements.
   *

   * but mutates {@code multisetToModify} instead of returning a view.
   *
   * <p>In contrast, {@code multisetToModify.retainAll(multisetToRetain)} keeps all occurrences of
   * elements that appear at all in {@code multisetToRetain}, and deletes all occurrences of all
   * other elements.
   *