contents = f.read()
    print(contents)
```

Underneath, the `open("./somefile.txt")` creates an object that is called a "Context Manager".

When the `with` block finishes, it makes sure to close the file, even if there were exceptions.

When you create a dependency with `yield`, **FastAPI** will internally create a context manager for it, and combine it with some other related tools.

// 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.
//
// You should have received a copy of the GNU Affero General Public License

	STREXD	R0, (R2), R1       // ERROR "cannot use same register as both source and destination"
	STREXD	R0, (R2), R2       // ERROR "cannot use same register as both source and destination"
	STREXD	R1, (R4), R7       // ERROR "must be even"
	STREXB	R0, (R2), R0       // ERROR "cannot use same register as both source and destination"
	STREXB	R0, (R2), R2       // ERROR "cannot use same register as both source and destination"

// 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.
//
// You should have received a copy of the GNU Affero General Public License

// 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.
//
// You should have received a copy of the GNU Affero General Public License

// 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.
//
// You should have received a copy of the GNU Affero General Public License

// 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.
//
// You should have received a copy of the GNU Affero General Public License

         * only possible value for the type parameter is <E>, since otherwise the
         * MultiExceptionListIterator wouldn't be an Iterator<E>. The cast is safe, even though
         * javac can't tell.
         */
        @SuppressWarnings("unchecked")
        MultiExceptionListIterator multiExceptionListIterator =
            (MultiExceptionListIterator) reference;

 * </ul>
 *
 * <h3>Warning about performance</h3>
 *
 * <p>Remember that parameter values for message construction must all be computed eagerly, and
 * autoboxing and varargs array creation may happen as well, even when the verification succeeds and
 * the message ends up unneeded. Performance-sensitive verification checks should continue to use
 * usual form:
 *
 * <pre>{@code
 * Bill bill = remoteService.getLastUnpaidBill();

   * '\\u5432'} would yield the byte array {@code {0x54, 0x32}}.
   *
   * <p>If you need to convert and concatenate several values (possibly even of different types),
   * use a shared {@link java.nio.ByteBuffer} instance, or use {@link
   * com.google.common.io.ByteStreams#newDataOutput()} to get a growable buffer.
   */
  @GwtIncompatible // doesn't work