## `Field`のインポート

まず、以下のようにインポートします:

```Python hl_lines="4"
{!../../docs_src/body_fields/tutorial001.py!}
```

/// warning | "注意"

`Field`は他の全てのもの（`Query`、`Path`、`Body`など）とは違い、`fastapi`からではなく、`pydantic`から直接インポートされていることに注意してください。

///

## モデルの属性の宣言

以下のように`Field`をモデルの属性として使用することができます:

          <association>
            <type>Reporting</type>
          </association>
        </field>
      </fields>
    </class>
    <class>
      <name>PluginContainer</name>
      <version>3.0.0+</version>
      <description>Contains the plugins information for the project.</description>
      <fields>
        <field>
          <name>plugins</name>
          <version>4.0.0+</version>

      <description>Root element of the {@code lifecycle.xml} file.</description>
      <fields>
        <field>
          <name>lifecycles</name>
          <version>1.0.0+</version>
          <association xml.itemsStyle="flat">
            <type>Lifecycle</type>
            <multiplicity>*</multiplicity>
          </association>
        </field>
      </fields>
    </class>
    <class>
      <name>Lifecycle</name>

            field.field_info.annotation
        ) and not isinstance(field.field_info, params.Body)

    def is_sequence_field(field: ModelField) -> bool:
        return field_annotation_is_sequence(field.field_info.annotation)

    def is_scalar_sequence_field(field: ModelField) -> bool:
        return field_annotation_is_scalar_sequence(field.field_info.annotation)

    def is_bytes_field(field: ModelField) -> bool:

        </field>
        <field>
          <name>exists</name>
          <version>1.0.0+</version>
          <type>String</type>
          <description>
            The name of the file that should exist to activate a profile. Please note, that missing and exists
            fields cannot be used together. Only one of them should be used at any one time.
          </description>
        </field>
      </fields>
    </class>

                if (isExcludeSearchword(words[i], fields != null && fields.length > 0 ? fields[0] : "", langs, analyzer)) {
                    continue;
                }

                final String word = normalizer.normalize(words[i], fields != null && fields.length > 0 ? fields[0] : "", langs);
                final List<String> l = readingConverter.convert(word, fields != null && fields.length > 0 ? fields[0] : "", langs);

      <version>1.0.0+</version>
      <fields>
        <field>
          <name>toolchains</name>
          <version>1.0.0+</version>
          <description>The toolchain instance definition.</description>
          <association xml.itemsStyle="flat">
            <type>ToolchainModel</type>
            <multiplicity>*</multiplicity>
          </association>
        </field>
      </fields>
    </class>
    <class>

		if fieldStruct := modelType.Field(i); ast.IsExported(fieldStruct.Name) {
			if field := schema.ParseField(fieldStruct); field.EmbeddedSchema != nil {
				schema.Fields = append(schema.Fields, field.EmbeddedSchema.Fields...)
			} else {
				schema.Fields = append(schema.Fields, field)
			}
		}
	}

	for _, field := range schema.Fields {
		if field.DBName == "" && field.DataType != "" {

index.field.config_id=config_id
index.field.expires=expires
index.field.url=url
index.field.doc_id=doc_id
index.field.id=_id
index.field.version=_version
index.field.seq_no=_seq_no
index.field.primary_term=_primary_term
index.field.lang=lang
index.field.has_cache=has_cache
index.field.last_modified=last_modified
index.field.anchor=anchor
index.field.segment=segment
index.field.role=role
index.field.boost=boost

                    final Map<String, Object> fields = searchHit.getSourceAsMap();
                    target.setParentUrl(getFieldValue(fields.get("parentUrl"), String.class));
                    target.setMethod(getFieldValue(fields.get("method"), String.class));
                    target.setMimeType(getFieldValue(fields.get("mimeType"), String.class));
                    target.setSessionId(getFieldValue(fields.get("sessionId"), String.class));