diff --git a/src/ContainerForm.php b/src/ContainerForm.php
index 1d4cf05dffb3104d8095b267ff62cfc604cd82be..9c7e339bef86aff91346c8a3dfe9321e384ee481 100644
--- a/src/ContainerForm.php
+++ b/src/ContainerForm.php
@@ -2,6 +2,7 @@
 
 namespace WPDesk\Forms;
 
+use Psr\Container\ContainerInterface;
 use WPDesk\Persistence\PersistentContainer;
 
 /**
@@ -11,7 +12,7 @@ use WPDesk\Persistence\PersistentContainer;
  */
 interface ContainerForm {
 	/**
-	 * @param \Psr\Container\ContainerInterface $data
+	 * @param ContainerInterface $data
 	 *
 	 * @return void
 	 */
diff --git a/src/Field/BasicField.php b/src/Field/BasicField.php
index 69e460dc4e30c4a655980a486dcad8680f181460..94449338e8e09fd932a81c2f394e3df46d50da44 100644
--- a/src/Field/BasicField.php
+++ b/src/Field/BasicField.php
@@ -124,7 +124,7 @@ abstract class BasicField implements Field {
 	}
 
 	public function get_possible_values() {
-		return isset( $this->meta['possible_values'] ) ? $this->meta['possible_values'] : [];
+		return $this->meta['possible_values'] ?? [];
 	}
 
 	public function get_id(): string {