if (to instanceof WildcardType) {
          return; // Okay to say Foo is <?>
        }
        // Can't map from a raw class to anything other than itself or a wildcard.
        // You can't say "assuming String is Integer".
        // And we don't support "assuming String is T"; user has to say "assuming T is String".

/// info

If you come from Flask, this would be the equivalent of Flask's Blueprints.

///

## An example file structure { #an-example-file-structure }

Let's say you have a file structure like this:

```
.
├── app
│   ├── __init__.py
│   ├── main.py
│   ├── dependencies.py
│   └── routers
│   │   ├── __init__.py
│   │   ├── items.py
│   │   └── users.py

{* ../../docs_src/python_types/tutorial008_py310.py hl[1] *}

This means:

* The variable `prices` is a `dict`:
    * The keys of this `dict` are of type `str` (let's say, the name of each item).
    * The values of this `dict` are of type `float` (let's say, the price of each item).

#### Union { #union }

You can declare that a variable can be any of **several types**, for example, an `int` or a `str`.

So you wait for your crush to finish the story (finish the current work ⏯ / task being processed 🤓), smile gently and say that you are going for the burgers ⏸.

## Custom response class { #custom-response-class }

You can create your own custom response class, inheriting from `Response` and using it.

For example, let's say that you want to use [`orjson`](https://github.com/ijl/orjson) with some settings.

Let's say you want it to return indented and formatted JSON, so you want to use the orjson option `orjson.OPT_INDENT_2`.

But it's signed. So, when you receive a token that you emitted, you can verify that you actually emitted it.

That way, you can create a token with an expiration of, let's say, 1 week. And then when the user comes back the next day with the token, you know that user is still logged in to your system.

Now you know that whenever you need them you can use them in **FastAPI**.

## Default values { #default-values }

You can, of course, use default values other than `None`.

Let's say that you want to declare the `q` query parameter to have a `min_length` of `3`, and to have a default value of `"fixedquery"`:

{* ../../docs_src/query_params_str_validations/tutorial005_an_py310.py hl[9] *}

/// note

type string string

// int is a signed integer type that is at least 32 bits in size. It is a
// distinct type, however, and not an alias for, say, int32.
type int int

// uint is an unsigned integer type that is at least 32 bits in size. It is a
// distinct type, however, and not an alias for, say, uint32.
type uint uint

// uintptr is an integer type that is large enough to hold the bit pattern of
// any pointer.
type uintptr uintptr

			if i%4 == 0 {
				m.Lock(id, source)
				acc0 -= 100
				acc1 += 100
				m.Unlock(b.Context())
			} else {
				for i := 0; i < len(data); i += 4 {
					data[i]++
				}
				// Elaborate way to say runtime.Gosched
				// that does not put the goroutine onto global runq.
				go func() {
					c <- true
				}()
				<-c
			}
		}
	})
}

func BenchmarkMutexSpin(b *testing.B) {

     * is that in JavaScript, a single quote must be escaped.</p>
     *
     * <p>Example:</p>
     * <pre>
     * input string: He didn't say, "Stop!"
     * output string: He didn't say, \"Stop!\"
     * </pre>
     *
     *
     * @param str  String to escape values in, may be null
     * @return String with escaped values, <code>null</code> if null string input
     */