### Holding multiple locks

You're allowed to take the Http2Connection lock while holding the Http2Writer lock. But not vice-versa. Because taking the Http2Writer lock can block.

## Dependencies with `yield` and `except`

If you catch an exception using `except` in a dependency with `yield` and you don't raise it again (or raise a new exception), FastAPI won't be able to notice there was an exception, the same way that would happen with regular Python:

//// tab | Python 3.9+

```Python hl_lines="15-16"
{!> ../../docs_src/dependencies/tutorial008c_an_py39.py!}
```

////

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *

/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *

 *
 * <h3>More information</h3>
 *
 * See <a href="https://github.com/google/guava/wiki/ConditionalFailuresExplained">Conditional
 * failures explained</a> in the Guava User Guide for advice on when this class should be used.
 *
 * @since 17.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class Verify {
  /**

    CHECK_EQ(TF_GetCode(status.get()), TF_OK) << TF_Message(status.get());
    if (dev_type == device_type) {
      *device_name = dev_name;
      LOG(INFO) << "Found " << device_type << " device " << *device_name;
      TF_DeleteDeviceList(devices);
      return true;
    }
  }
  TF_DeleteDeviceList(devices);
  return false;
}

message LocalVolumeSource {
  // path of the full path to the volume on the node.
  // It can be either a directory or block device (disk, partition, ...).
  optional string path = 1;

  // fsType is the filesystem type to mount.
  // It applies only when the Path is a block device.
  // Must be a filesystem type supported by the host operating system.

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *

 *
 * <h3>More information</h3>
 *
 * See <a href="https://github.com/google/guava/wiki/ConditionalFailuresExplained">Conditional
 * failures explained</a> in the Guava User Guide for advice on when this class should be used.
 *
 * @since 17.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class Verify {
  /**