Let's take this application as example:

{* ../../docs_src/query_params_str_validations/tutorial001_py310.py hl[7] *}

The query parameter `q` is of type `str | None`, that means that it's of type `str` but could also be `None`, and indeed, the default value is `None`, so FastAPI will know it's not required.

/// note

	DiskID  string `msg:"id"`
	Metrics bool   `msg:"m"`
	NoOp    bool   `msg:"np"`
}

// DiskInfo is an extended type which returns current
// disk usage per path.
// The above means that any added/deleted fields are incompatible.
//
// The above means that any added/deleted fields are incompatible.
//
//msgp:tuple DiskInfo
type DiskInfo struct {
	Total      uint64
	Free       uint64
	Used       uint64
	UsedInodes uint64

#              , EmptyString, FromTo, DateFromTo, RangeOf, ...
#              , (and prefix '!' means excluding, '%' means reviving)
# table: table name (hint) or $$ALL$$
# column: column name (hint) or $$CommonColumn$$ or $$VersionNo$$
#
# Example:
# map:{
#     # This means that String includes GreaterThan at MEMBER.MEMBER_ACCOUNT only
#     # and LessThan at PRODUCT.PRODUCT_NAME and PRODUCT.PRODUCT_HANDLE_CODE,

they've begun asking riddles.--I believe I can guess that,' she
added aloud.

  `Do you mean that you think you can find out the answer to it?'
said the March Hare.

  `Exactly so,' said Alice.

  `Then you should say what you mean,' the March Hare went on.

  `I do,' Alice hastily replied; `at least--at least I mean what
I say--that's the same thing, you know.'

### How the importing works { #how-the-importing-works }

The section:

```Python
from .routers import items, users
```

means:

* Starting in the same package that this module (the file `app/main.py`) lives in (the directory `app/`)...
* look for the subpackage `routers` (the directory at `app/routers/`)...

    int INCLUDE_ARTIFACT = 4;

    int OMIT_FOR_NEARER = 5;

    int UPDATE_SCOPE = 6;

    @Deprecated
    int MANAGE_ARTIFACT = 7;

    int OMIT_FOR_CYCLE = 8;

    /**
     * this event means that the artifactScope has NOT been updated to a farther node artifactScope because current
     * node is in the first level pom
     */
    int UPDATE_SCOPE_CURRENT_POM = 9;

    int SELECT_VERSION_FROM_RANGE = 10;

      return;
    }

    /*
     * Any of the setException() calls below can fail if the output Future is cancelled between now
     * and then. This means that we're silently swallowing an exception -- maybe even an Error. But
     * this is no worse than what FutureTask does in that situation. Additionally, because the

     * <br/>
     * Note: the <code>&gt;</code> means project level, while <code>&gt;&gt;</code> means global (whole session level,
     * so even plugins will get relocated artifacts) relocation.
     * <br/>
     * For example,
     * <pre>maven.relocations.entries = org.foo:*:*>, \\<br/>    org.here:*:*>org.there:*:*, \\<br/>    javax.inject:javax.inject:1>>jakarta.inject:jakarta.inject:1.0.5</pre>

menu, a prominent item in the list meets this criterion.

  1. Source Code.

  The "source code" for a work means the preferred form of the work
for making modifications to it.  "Object code" means any non-source
form of a work.

  A "Standard Interface" means an interface that either is an official
standard defined by a recognized standards body, or, in the case of

  h. Licensor means the individual(s) or entity(ies) granting rights
     under this Public License.

  i. Share means to provide material to the public by any means or
     process that requires permission under the Licensed Rights, such
     as reproduction, public display, public performance, distribution,
     dissemination, communication, or importation, and to make material