쿼리 매개변수를 선언할 때와 같이, 모델 어트리뷰트가 기본 값을 가지고 있어도 이는 필수가 아닙니다. 그외에는 필수입니다. 그저 `None`을 사용하여 선택적으로 만들 수 있습니다.

예를 들면, 위의 이 모델은 JSON "`object`" (혹은 파이썬 `dict`)을 다음과 같이 선언합니다:

```JSON
{
    "name": "Foo",
    "description": "선택적인 설명란",
    "price": 45.2,
    "tax": 3.5
}
```

...`description`과 `tax`는 (기본 값이 `None`으로 되어 있어) 선택적이기 때문에, 이 JSON "`object`"는 다음과 같은 상황에서도 유효합니다:

```JSON
{
    "name": "Foo",

ret=$?

if [ $ret != 0 ] ; then
  for f in `find ./target -type f | grep surefire-reports | grep -v /TEST-` ; do
    cat $f
  done
fi

import static com.google.common.collect.testing.Helpers.assertContentsInOrder;
import static com.google.common.collect.testing.features.CollectionFeature.SUPPORTS_REMOVE;
import static com.google.common.collect.testing.features.CollectionSize.ONE;
import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
import static com.google.common.collect.testing.features.CollectionSize.ZERO;
import static java.util.Arrays.asList;

		return true
	}
	return false
}

// IsPPC64CMP reports whether the op (as defined by an ppc64.A* constant) is
// one of the CMP instructions that require special handling.
func IsPPC64CMP(op obj.As) bool {
	switch op {

        List<AvPair> pairs = AvPairs.decode(fullData);

        assertNotNull(pairs, "Decoded pairs should not be null");
        assertEquals(1, pairs.size(), "Should have decoded one pair");

        AvPair pair = pairs.get(0);
        assertEquals(AvPair.MsvAvFlags, pair.getType(), "Pair type should be MsvAvFlags");
        assertTrue(pair instanceof AvFlags, "Should be decoded as AvFlags");

          echo "Database initialized successfully";
          break;
        fi;
        echo "Waiting for database to be ready... ($$counter/12)";
        sleep 5;
        counter=$$(($$counter + 1));
      done;
      # timeout handling
      if [ $$counter -gt 20 ]; then
        echo "Error: Database failed to start within timeout";
        exit 1;
      fi;

#!/usr/bin/env bash

set -e

export GORACE="history_size=7"
export MINIO_API_REQUESTS_MAX=10000

for d in $(go list ./...); do
	CGO_ENABLED=1 go test -v -race --timeout 100m "$d"

			wantOk:       true,
		},
		{
			name:         "one zero, below quorum",
			m:            metaCacheEntries{inputSerialized[0], inputSerialized[0], inputSerialized[0], metaCacheEntry{}},
			r:            metadataResolutionParams{dirQuorum: 4, objQuorum: 4, strict: false},
			wantSelected: nil,
			wantOk:       false,
		},
		{
			name:         "one zero, below quorum, strict",

│   │   ├── items.py
│   │   └── users.py
│   └── internal
│       ├── __init__.py
│       └── admin.py
```

/// tip

There are several `__init__.py` files: one in each directory or subdirectory.

This is what allows importing code from one file into another.

For example, in `app/main.py` you could have a line like:

```
from app.routers import items
```

///

    extends AbstractImmutableMapMapInterfaceTest<String, Integer> {
  @Override
  protected Map<String, Integer> makePopulatedMap() {
    return ImmutableMap.of("one", 1);
  }

  @Override
  protected String getKeyNotInPopulatedMap() {
    return "minus one";
  }

  @Override
  protected Integer getValueNotInPopulatedMap() {
    return -1;
  }