///

### Import `Depends` { #import-depends }

{* ../../docs_src/dependencies/tutorial001_an_py310.py hl[3] *}

### Declare the dependency, in the "dependant" { #declare-the-dependency-in-the-dependant }

The same way you use `Body`, `Query`, etc. with your *path operation function* parameters, use `Depends` with a new parameter:

name is a type or an ordinary identifier, so there will be no syntax
errors that might stop parsing early.

An error on not-declared:1 indicates that foo is undeclared.
An error on not-type:1 indicates that foo is not a type (if declared at all, it is an identifier).
An error on not-int-const:1 indicates that foo is not an integer constant.
An error on not-num-const:1 indicates that foo is not a number constant.

      incorporateRequirements(requirements, moreRequirements, testerAnnotation);
    }

    return requirements;
  }

  /**
   * Find all the tester annotations declared on a tester class or method.
   *
   * @param classOrMethod a class or method whose tester annotations to find
   * @return an iterable sequence of tester annotations on the class
   */

  }

  /**
   * Compares two comparable objects as specified by {@link Comparable#compareTo}, <i>if</i> the
   * result of this comparison chain has not already been determined.
   *
   * <p>This method is declared to accept any 2 {@code Comparable} objects, even if they are not <a
   * href="https://docs.oracle.com/javase/tutorial/collections/interfaces/order.html">mutually

        } catch (final NoSuchFieldException e) {
            throw new NoSuchFieldRuntimeException(clazz, name, e);
        }
    }

    /**
     * Returns a {@link Field} object that reflects the specified declared field of the class or interface represented by the {@link Class} object.
     *
     * @param clazz
     *            The {@link Class} object representing the class. Must not be {@literal null}.
     * @param name

      incorporateRequirements(requirements, moreRequirements, testerAnnotation);
    }

    return requirements;
  }

  /**
   * Find all the tester annotations declared on a tester class or method.
   *
   * @param classOrMethod a class or method whose tester annotations to find
   * @return an iterable sequence of tester annotations on the class
   */

q: Annotated[str | None, Query(min_length=3)] = None
```

////

So, when you need to declare a value as required while using `Query`, you can simply not declare a default value:

{* ../../docs_src/query_params_str_validations/tutorial006_an_py39.py hl[9] *}

### Required, can be `None` { #required-can-be-none }

But if you return a `Response` directly (or any subclass, like `JSONResponse`), the data won't be automatically converted (even if you declare a `response_model`), and the documentation won't be automatically generated (for example, including the specific "media type", in the HTTP header `Content-Type` as part of the generated OpenAPI).

If you go to `/docs`, you will see that it has the **schemas** for the data to be sent in requests and received in responses:

<img src="/img/tutorial/generate-clients/image01.png">

You can see those schemas because they were declared with the models in the app.

That information is available in the app's **OpenAPI schema**, and then shown in the API docs.

      <artifactId>guava</artifactId>
      <version>${project.version}</version>
    </dependency>
    <!-- We redeclare the j2objc-annotations dependency from `guava`: Our Gradle
         Module Metadata hides the dependency declared in `guava` from runtime
         configurations downstream, and GWT uses the runtime configuration for
         its builds. Thus, GWT doesn't get j2objc-annotations transitively, in