Most of these ideas would be more or less **independent**, and in most cases you should only need to study them if they apply directly to **your project**.

If something seems interesting and useful to your project, go ahead and check it, but otherwise, you might probably just skip them.

/// tip

If you want to **learn FastAPI** in a structured way (recommended), go and read the [Tutorial - User Guide](../tutorial/index.md) chapter by chapter instead.

 *
 * @author Mike Bostock
 * @author Louis Wasserman
 * @since 2.0
 */
@GwtCompatible
/*
 * We provide and encourage use of ForwardingNavigableSet over this class, but we still provide this
 * one to preserve compatibility.
 */
@SuppressWarnings("JdkObsolete")
public abstract class ForwardingSortedMap<K extends @Nullable Object, V extends @Nullable Object>

@GwtCompatible
public enum CollectionFeature implements Feature<Collection> {
  /**
   * The collection must not throw {@code NullPointerException} on calls such as {@code
   * contains(null)} or {@code remove(null)}, but instead must return a simple {@code false}.
   */
  ALLOWS_NULL_QUERIES,
  ALLOWS_NULL_VALUES(ALLOWS_NULL_QUERIES),

  /**
   * Indicates that a collection disallows certain elements (other than {@code null}, whose validity

    }

    @Test
    @DisplayName("writeAndXWireFormat with andx but batching prevented by limit")
    void testWriteAndXWireFormatBatchingPrevented() {
        DummyPlainSMB next = new DummyPlainSMB();
        DummyAndXBlock block = new DummyAndXBlock(next);
        block.customBatchLimit = 1; // allow 1, but we'll set batchLevel to meet limit
        block.batchLevel = 1; // batchLevel >= limit prevents chaining

IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)...

https://github.com/google/guava/wiki/HowToContribute#code-contributions
and
https://github.com/google/guava/blob/master/CONTRIBUTING.md
before sending a pull request.

We generally welcome PRs for fixing trivial bugs or typos, but please refrain
from sending a PR with significant changes unless explicitly requested.

```python
from fastapi import Depends
```

::: fastapi.Depends

## `Security()`

For many scenarios, you can handle security (authorization, authentication, etc.) with dependencies, using `Depends()`.

But when you want to also declare OAuth2 scopes, you can use `Security()` instead of `Depends()`.

You can import `Security()` directly from `fastapi`:

```python
from fastapi import Security
```

    }
  }

  /**
   * Creates any necessary but nonexistent parent directories of the specified file. Note that if
   * this operation fails it may have succeeded in creating some (but not all) of the necessary
   * parent directories.
   *
   * @throws IOException if an I/O error occurs, or if any necessary but nonexistent parent
   *     directories of the specified file could not be created.

 Copyright (C) 1991, 1999 Free Software Foundation, Inc.
 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.

(This is the first released version of the Lesser GPL.  It also counts
 as the successor of the GNU Library Public License, version 2, hence
 the version number 2.1.)

// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//