{* ../../docs_src/query_params_str_validations/tutorial014_an_py310.py hl[10] *}

## Custom Validation { #custom-validation }

There could be cases where you need to do some **custom validation** that can't be done with the parameters shown above.

## Where are Packages Installed { #where-are-packages-installed }

When you install Python, it creates some directories with some files in your computer.

Some of these directories are the ones in charge of having all the packages you install.

    public String available;

    /** Access permissions for documents from this data source */
    @CustomSize(maxKey = "form.admin.max.input.size")
    public String permissions;

    /** Virtual hosts where this configuration applies */
    @CustomSize(maxKey = "form.admin.max.input.size")
    public String virtualHosts;

    /** Sort order for displaying configurations */
    @Required
    @Min(value = 0)

            }

            from(src) {
                eachFile {
                    // Remove top folder when unzipping, that way we get rid of Android Studio.app folder that can cause issues on Mac
                    // where MacOS would kill the Android Studio process right after start, issue: https://github.com/gradle/gradle-profiler/issues/469
                    @Suppress("SpreadOperator")

  val isResponseComplete: Boolean

  /** The socket that carries this exchange. */
  val socket: Socket

  /** Returns an output stream where the request body can be streamed. */
  @Throws(IOException::class)
  fun createRequestBody(
    request: Request,
    contentLength: Long,
  ): Sink

          public <T extends @Nullable Object> T[] toArray(T[] array) {
            T[] result = super.toArray(array);
            if (size() < result.length) {
              // It works around a GWT bug where elements after last is not
              // properly null'ed.
              @Nullable Object[] unsoundlyCovariantArray = result;
              unsoundlyCovariantArray[size()] = null;
            }

There is some assistance in the IDE for this plus a lot of validation that is applied at build time and on CI, but it is useful to keep these constraints in mind as well.

See [Gradle runtimes](runtimes.md) for a list of these runtimes and more details.

### Build execution model

     * This means that developer will either have to type groupId or wait for build execution of all modules which
     *   were fine, but they are still before one which reported errors.
     * <p>Then the returned value is {@code groupId:artifactId} when there is a name clash and
     * {@code :artifactId} if there is no conflict.
     * This method is made package-private for testing purposes.
     *

      summary: List favorites
      description: Returns favorited document IDs
      operationId: listFavorites
      parameters:
        - name: queryId
          in: query
          description: Query ID where the document is contained
          required: true
          schema:
            type: string
            example: queryid
      responses:
        '200':
          description: Successful operation

			// since Linux 4.11.
			_ = syscall.SetsockoptInt(fd, syscall.IPPROTO_TCP, unix.TCP_FASTOPEN_CONNECT, 1)

			// Enable TCP quick ACK, John Nagle says
			// "Set TCP_QUICKACK. If you find a case where that makes things worse, let me know."
			_ = syscall.SetsockoptInt(fd, syscall.IPPROTO_TCP, unix.TCP_QUICKACK, 1)

			/// Enable keep-alive
			{
				_ = unix.SetsockoptInt(fd, unix.SOL_SOCKET, unix.SO_KEEPALIVE, 1)