```Python hl_lines="8  10"
{!> ../../docs_src/query_params/tutorial004.py!}
```

////

## Required query parameters

When you declare a default value for non-path parameters (for now, we have only seen query parameters), then it is not required.

If you don't want to add a specific value but just make it optional, set the default as `None`.

     * 
     * @see DialectVersion
     * @return minimum protocol version to use/allow
     * @since 2.1
     */
    DialectVersion getMinimumVersion ();


    /**
     * Maximum protocol version
     * 
     * Property <tt>jcifs.smb.client.maxVersion</tt> (string, default SMB210)
     * 
     * @see DialectVersion
     * @return maximum protocol version to use/allow

		if v == "" && equals(k, xhttp.AmzObjectLockMode, xhttp.AmzObjectLockRetainUntilDate) {
			continue
		}

		if stringsHasPrefixFold(k, ReservedMetadataPrefixLower) {
			// Do not need to send any internal metadata
			// values to client.
			continue
		}

		// https://github.com/google/security-research/security/advisories/GHSA-76wf-9vgp-pj7w

You can also use the <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/PATCH" class="external-link" target="_blank">HTTP `PATCH`</a> operation to *partially* update data.

This means that you can send only the data that you want to update, leaving the rest intact.

/// note

`PATCH` is less commonly used and known than `PUT`.

And many teams use only `PUT`, even for partial updates.

    /** Constructor for use by subclasses. */
    protected SleepingStopwatch() {}

    /*
     * We always hold the mutex when calling this. TODO(cpovirk): Is that important? Perhaps we need
     * to guarantee that each call to reserveEarliestAvailable, etc. sees a value >= the previous?
     * Also, is it OK that we don't hold the mutex when sleeping?
     */
    protected abstract long readMicros();

   * environment? If the latter, maybe write a custom Executor that avoids failing the test when it
   * sees an Error?
   */
  @AndroidIncompatible
  public void testTaskThrowsError() throws Exception {
    class MyError extends Error {}
    final CyclicBarrier barrier = new CyclicBarrier(2);
    // we need to make sure the error gets thrown on a different thread.
    ExecutorService service = Executors.newSingleThreadExecutor();

      for (int insertion = 0; insertion < totalInsertions; insertion++) {
        RandomHasherAction.pickAtRandom(random).performAction(random, sinksAndControl);
      }
      // We need to ensure that at least 4 bytes have been put into the hasher or else
      // Hasher#hash will throw an ISE.
      int intToPut = random.nextInt();
      for (Hasher hasher : sinksAndControl) {

# Body - Multiple Parameters

Now that we have seen how to use `Path` and `Query`, let's see more advanced uses of request body declarations.

## Mix `Path`, `Query` and body parameters

First, of course, you can mix `Path`, `Query` and request body parameter declarations freely and **FastAPI** will know what to do.

And you can also declare body parameters as optional, by setting the default to `None`:

//// tab | Python 3.10+

		{seek: io.SeekCurrent, off: 1, wantpos: 1<<33 + 1, readerr: io.EOF},
		{seek: io.SeekStart, n: 5, want: "01234"},
		{seek: io.SeekCurrent, n: 5, want: "56789"},
		{seek: io.SeekEnd, off: -1, n: 1, wantpos: 9, want: "9"},
	}

	for i, tt := range tests {
		pos, err := r.Seek(tt.off, tt.seek)
		if err == nil && tt.seekerr != "" {
			t.Errorf("%d. want seek error %q", i, tt.seekerr)
			continue
		}

/// tip

This is a somewhat advanced technique, and in most of the cases you won't really need it, as you can raise exceptions (including `HTTPException`) from inside of the rest of your application code, for example, in the *path operation function*.

But it's there for you if you need it. 🤓

///

//// tab | Python 3.9+

```Python hl_lines="18-22  31"