Described a bit topic base class and methods.

src/Topic/TopicBase.php

@@ -2,8 +2,37 @@
 
 namespace Toloka\PhpApi;
 
-abstract class TopicBase implements TopicInterface {
+class TopicBase implements TopicInterface {
 
+  protected Client $client;
 
+  protected int $id;
+
+  public function __construct(
+    Client $client
+  ) {
+    $this->client = $client;
+  }
+
+  /**
+   * @return int
+   */
+  public function id(): int {
+    return $this->id;
+  }
+
+  /**
+   * @param int $id
+   */
+  public function setId(int $id): void {
+    $this->id = $id;
+  }
+
+  /**
+   * {@inheritDoc}
+   */
+  public function url(bool $absolute = TRUE): string {
+    return $this->client->getBaseUrl() . 't' . $this->id();
+  }
 
 }