It is just a standard function that can receive parameters.

It can be an `async def` or normal `def` function, **FastAPI** will know how to handle it correctly.

In this case, the task function will write to a file (simulating sending an email).

And as the write operation doesn't use `async` and `await`, we define the function with normal `def`:

{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}

## Add the background task

			Err:  syscall.EISDIR,
		}
	}

	return &LockedFile{f}, nil
}

// TryLockedOpenFile - tries a new write lock, functionality
// it is similar to LockedOpenFile with with syscall.LOCK_EX
// mode but along with syscall.LOCK_NB such that the function
// doesn't wait forever but instead returns if it cannot
// acquire a write lock.
func TryLockedOpenFile(path string, flag int, perm os.FileMode) (*LockedFile, error) {

 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package jcifs.netbios;


import jcifs.Configuration;

 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package jcifs.smb1.smb1;

class SmbComCreateDirectory extends ServerMessageBlock {

 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package jcifs.util;


import jcifs.Encodable;


/**
 * @author mbechler
 *
 */

	marshalledJSON = append(marshalledJSON, "\n"...)

	return writeCNIConfig(ctx, marshalledJSON, cfg)
}

// writeCNIConfig will
// 1. read in the existing CNI config file
// 2. append the `istio`-specific entry
// 3. write the combined result back out to the same path, overwriting the original.
func writeCNIConfig(ctx context.Context, pluginConfig []byte, cfg *config.InstallConfig) (string, error) {

# for the file, adds it to the host KUBECONFIG, and creates a mount for it. Note that we use a copy
# of the original file, so that the container can write to it.
add_KUBECONFIG_if_exists () {
  if [[ -f "$1" ]]; then
    local local_config
    local_config="$(mktemp)"
    cp "${1}" "${local_config}"

   * segments, each governed by its own write lock. The segment lock is taken once for each explicit
   * write, and twice for each cache loading computation (once prior to loading the new value, and
   * once after loading completes). Much internal cache management is performed at the segment
   * granularity. For example, access queues and write queues are kept per segment when they are

 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package jcifs.ntlmssp.av;


/**
 * @author mbechler
 *
 */
public class AvPair {

    /**

 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package jcifs.ntlmssp.av;


import jcifs.Configuration;
import jcifs.internal.util.SMBUtil;


/**