diff --git a/src/Numerics/Range.php b/src/Numerics/Range.php
index f49add5..41685b0 100644
--- a/src/Numerics/Range.php
+++ b/src/Numerics/Range.php
@@ -9,7 +9,7 @@ use Exception;
 
 class Range
 {
-    public function __construct(private int $min, private int $max)
+    final public function __construct(private int $min, private int $max)
     {
         if ($min > $max) {
             throw new Exception('min > max');
@@ -26,9 +26,9 @@ class Range
         return $this->max;
     }
 
-    protected static function create(int $min, int $max): self
+    protected static function create(int $min, int $max): static
     {
-        return new Range($min, $max);
+        return new static($min, $max);
     }
 
     // REVIEW: It's probably bad form to have access statics via a derived class, but the syntax looks better :-)
diff --git a/src/PlayersRange.php b/src/PlayersRange.php
index ea465f6..3ceb1ee 100644
--- a/src/PlayersRange.php
+++ b/src/PlayersRange.php
@@ -6,8 +6,8 @@ use DNW\Skills\Numerics\Range;
 
 class PlayersRange extends Range
 {
-    protected static function create(int $min, int $max): self
+    protected static function create(int $min, int $max): static
     {
-        return new PlayersRange($min, $max);
+        return new static($min, $max);
     }
 }
diff --git a/src/TeamsRange.php b/src/TeamsRange.php
index 19261a4..7d53bef 100644
--- a/src/TeamsRange.php
+++ b/src/TeamsRange.php
@@ -6,8 +6,8 @@ use DNW\Skills\Numerics\Range;
 
 class TeamsRange extends Range
 {
-    protected static function create(int $min, int $max): self
+    protected static function create(int $min, int $max): static
     {
-        return new TeamsRange($min, $max);
+        return new static($min, $max);
     }
 }
diff --git a/src/TrueSkill/Layers/PlayerPriorValuesToSkillsLayer.php b/src/TrueSkill/Layers/PlayerPriorValuesToSkillsLayer.php
index 6b9f893..55fa357 100644
--- a/src/TrueSkill/Layers/PlayerPriorValuesToSkillsLayer.php
+++ b/src/TrueSkill/Layers/PlayerPriorValuesToSkillsLayer.php
@@ -61,7 +61,6 @@ class PlayerPriorValuesToSkillsLayer extends TrueSkillFactorGraphLayer
 
     private function createPriorFactor(Rating $priorRating, Variable $skillsVariable): GaussianPriorFactor
     {
-        echo (get_class($this->getParentFactorGraph()).PHP_EOL);
         return new GaussianPriorFactor(
             $priorRating->getMean(),
             BasicMath::square($priorRating->getStandardDeviation()) +