public void testStringConverter_convert() {
    Converter<String, Float> converter = Floats.stringConverter();
    assertThat(converter.convert("1.0")).isEqualTo(1.0f);
    assertThat(converter.convert("0.0")).isEqualTo(0.0f);
    assertThat(converter.convert("-1.0")).isEqualTo(-1.0f);
    assertThat(converter.convert("1")).isEqualTo(1.0f);
    assertThat(converter.convert("0")).isEqualTo(0.0f);

Então, mesmo com o código acima que não usa Pydantic explicitamente, o FastAPI está usando Pydantic para converter essas dataclasses padrão para a versão do Pydantic.

E claro, ele suporta o mesmo:

* validação de dados
* serialização de dados
* documentação de dados, etc.

     * @return The converted {@link BigDecimal}
     */
    public static BigDecimal toBigDecimal(final Object o) {
        return toBigDecimal(o, null);
    }

    /**
     * Converts to {@link BigDecimal}.
     *
     * @param o
     *            The object to convert
     * @param pattern
     *            The pattern string
     * @return The converted {@link BigDecimal}
     */

   *       the same.
   *   <li>The special characters ".", "-", "*", and "_" remain the same.
   *   <li>The space character " " is converted into a plus sign "+".
   *   <li>All other characters are converted into one or more bytes using UTF-8 encoding and each
   *       byte is then represented by the 3-character string "%XY", where "XY" is the two-digit,

  }

  /**
   * Returns a serializable {@code Converter} that converts strings from this format to {@code
   * targetFormat}.
   *
   * @since 16.0
   */
  public Converter<String, String> converterTo(CaseFormat targetFormat) {
    return new StringConverter(this, targetFormat);
  }

  private static final class StringConverter extends Converter<String, String>
      implements Serializable {

    # with forward slashes, e.g. 'C:/Program Files', instead of
    # '/c/Program Files', thus becoming converted simply by virtue of having
    # been read.
    converted_vars[var] = value

  var_str = '\n'.join(f'{k}="{v}"'
                      for k, v in converted_vars.items())
  # The string can then be piped into `source`, to re-set the
  # 'converted' variables.
  print(var_str)


if __name__ == '__main__':

                    "description": "A very nice Item",
                    "price": 35.4,
                    "tax": 3.2,
                },
            },
            "converted": {
                "summary": "An example with converted data",
                "description": "FastAPI can convert price `strings` to actual `numbers` automatically",
                "value": {
                    "name": "Bar",

     */
    public static final ArtifactStatus GENERATED = new ArtifactStatus("generated", 1);

    /**
     * Low trust - was converted from the Maven 1.x repository.
     */
    public static final ArtifactStatus CONVERTED = new ArtifactStatus("converted", 2);

    /**
     * Moderate trust - it was deployed directly from a partner.
     */

It would also mean that if you get data from the `Request` object directly (for example, read the body) it won't be validated, converted or documented (with OpenAPI, for the automatic API user interface) by FastAPI.

Although any other parameter declared normally (for example, the body with a Pydantic model) would still be validated, converted, annotated, etc.

But there are specific cases where it's useful to get the `Request` object.

     * Returns the OS full name as reported by the system property "os.name".
     * The value is converted to lowercase for consistency.
     *
     * @return the operating system name (never null)
     */
    @Nonnull
    String name();

    /**
     * Returns the OS architecture as reported by the system property "os.arch".
     * The value is converted to lowercase for consistency.
     *