<name>Chris Povirk</name>
      <email>******@****.***</email>
    </developer>
  </developers>
  <modules>
    <module>guava</module>
    <module>guava-bom</module>
    <module>guava-gwt</module>
    <module>guava-testlib</module>
    <module>guava-tests</module>
  </modules>
  <scm>
    <connection>scm:git:https://github.com/google/guava.git</connection>

在这里，我们在 Pydantic 的 `Settings` 类中创建了一个名为 `Config` 的类，并将 `env_file` 设置为我们想要使用的 dotenv 文件的文件名。

/// tip

`Config` 类仅用于 Pydantic 配置。您可以在<a href="https://docs.pydantic.dev/latest/api/config/" class="external-link" target="_blank">Pydantic Model Config</a>中阅读更多相关信息。

///

### 使用 `lru_cache` 仅创建一次 `Settings`

从磁盘中读取文件通常是一项耗时的（慢）操作，因此您可能希望仅在首次读取后并重复使用相同的设置对象，而不是为每个请求都读取它。

但是，每次执行以下操作：

```Python
Settings()
```

#### `RequestValidationError`と`ValidationError`

/// warning | 注意

これらは今のあなたにとって重要でない場合は省略しても良い技術的な詳細です。

///

`RequestValidationError`はPydanticの<a href="https://docs.pydantic.dev/latest/concepts/models/#error-handling" class="external-link" target="_blank">`ValidationError`</a>のサブクラスです。

**FastAPI** は`response_model`でPydanticモデルを使用していて、データにエラーがあった場合、ログにエラーが表示されるようにこれを使用しています。

It can't handle nested models very well. So, if the JSON body in the request is a JSON object that has inner fields that in turn are nested JSON objects, it cannot be properly documented and validated.

/// check | Inspired **FastAPI** to

   * stripes, the intended concurrency level, and the typical number of keys used in a {@code
   * bulkGet(keys)} operation. See <a href="http://www.mathpages.com/home/kmath199.htm">Balls in
   * Bins model</a> for mathematical formulas that can be used to estimate the probability of
   * collisions.
   *
   * @param keys arbitrary non-null keys

### Concurrency + Parallelism: Web + Machine Learning { #concurrency-parallelism-web-machine-learning }

import java.util.LinkedHashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.function.UnaryOperator;

import org.apache.maven.impl.model.DefaultInterpolator;

/**
 * Enhancement of the standard <code>Properties</code>
 * managing the maintain of comments, etc.
 */
public class MavenProperties extends AbstractMap<String, String> {

import java.util.LinkedHashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.function.UnaryOperator;

import org.apache.maven.impl.model.DefaultInterpolator;

/**
 * Enhancement of the standard <code>Properties</code>
 * managing the maintain of comments, etc.
 */
@Deprecated
public class MavenProperties extends AbstractMap<String, String> {

	Float  DataType = "float"
	String DataType = "string"
	Time   DataType = "time"
	Bytes  DataType = "bytes"
)

const DefaultAutoIncrementIncrement int64 = 1

// Field is the representation of model schema's field
type Field struct {
	Name                   string
	DBName                 string
	BindNames              []string
	EmbeddedBindNames      []string
	DataType               DataType

```Python
from datetime import date

from pydantic import BaseModel

# Declare a variable as a str
# and get editor support inside the function
def main(user_id: str):
    return user_id


# A Pydantic model
class User(BaseModel):
    id: int
    name: str
    joined: date
```

これは以下のように用いられます:

```Python
my_user: User = User(id=3, name="John Doe", joined="2018-07-19")

second_user_data = {