// name is allowed to be "" to represent the legacy, ungroupified resources.
  // More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
  // +optional
  optional k8s.io.apimachinery.pkg.apis.meta.v1.ObjectMeta metadata = 1;

  // versions are the versions supported in this group. They are sorted in descending order of preference,
  // with the preferred version being the first entry.

        // v1 == 0.
        .optional(defaultValue = 0),
      Adapters.INTEGER_AS_BIG_INTEGER,
      algorithmIdentifier,
      name,
      validity,
      name,
      subjectPublicKeyInfo,
      Adapters.BIT_STRING.withTag(tag = 1L).optional(),
      Adapters.BIT_STRING.withTag(tag = 2L).optional(),
      extension.asSequenceOf().withExplicitBox(tag = 3).optional(defaultValue = listOf()),
      decompose = {

  // +optional
  optional k8s.io.apimachinery.pkg.apis.meta.v1.ObjectMeta metadata = 1;

  // provisioner indicates the type of the provisioner.
  optional string provisioner = 2;

  // parameters holds the parameters for the provisioner that should
  // create volumes of this storage class.
  // +optional
  map<string, string> parameters = 3;

            throw new LookupException(e);
        }
    }

    @Override
    public <T> Optional<T> lookupOptional(Class<T> type) {
        try {
            return Optional.of(container.lookup(type));
        } catch (ComponentLookupException e) {
            if (e.getCause() instanceof NoSuchElementException) {
                return Optional.empty();
            }
            throw new LookupException(e);
        }
    }

from typing import Optional

from fastapi import FastAPI
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()


class SubModel(BaseModel):
    a: Optional[str] = "foo"


class Model(BaseModel):
    x: Optional[int] = None
    sub: SubModel


class ModelSubclass(Model):
    y: int
    z: int = 0
    w: Optional[int] = None


class ModelDefaults(BaseModel):

#### Custom Resource Definitions (CRDs)
* [alpha] The CustomResourceDefinition API can now optionally
  [validate custom objects](https://kubernetes.io/docs/tasks/access-kubernetes-api/extend-api-custom-resource-definitions/#validation)
  based on a JSON schema provided in the CRD spec.

message StorageVersionCondition {
  // Type of the condition.
  // +required
  optional string type = 1;

  // Status of the condition, one of True, False, Unknown.
  // +required
  optional string status = 2;

  // If set, this represents the .metadata.generation that the condition was set based upon.
  // +optional
  optional int64 observedGeneration = 3;

@REM
@REM   JAVA_HOME           (Optional) Points to a Java installation.
@REM   MAVEN_BATCH_ECHO    (Optional) Set to 'on' to enable the echoing of the batch commands.
@REM   MAVEN_BATCH_PAUSE   (Optional) set to 'on' to wait for a key stroke before ending.
@REM   MAVEN_OPTS          (Optional) Java runtime options used when Maven is executed.
@REM   MAVEN_SKIP_RC       (Optional) Flag to disable loading of mavenrc files.

  // +optional
  optional k8s.io.apimachinery.pkg.apis.meta.v1.ObjectMeta metadata = 1;

  // Specification of the desired behavior of the PodDisruptionBudget.
  // +optional
  optional PodDisruptionBudgetSpec spec = 2;

  // Most recently observed status of the PodDisruptionBudget.
  // +optional
  optional PodDisruptionBudgetStatus status = 3;
}

            ),
        ],
        scheme_name: Annotated[
            Optional[str],
            Doc(
                """
                Security scheme name.

                It will be included in the generated OpenAPI (e.g. visible at `/docs`).
                """
            ),
        ] = None,
        description: Annotated[
            Optional[str],
            Doc(
                """