Upgrade with rector

src/FactorGraphs/Variable.php

@@ -2,18 +2,15 @@
 
 namespace DNW\Skills\FactorGraphs;
 
-class Variable
+class Variable implements \Stringable
 {
     private $_name;
 
-    private $_prior;
-
     private $_value;
 
-    public function __construct($name, $prior)
+    public function __construct($name, private $_prior)
     {
         $this->_name = 'Variable['.$name.']';
-        $this->_prior = $prior;
         $this->resetToPrior();
     }
 
@@ -32,7 +29,7 @@ class Variable
         $this->_value = $this->_prior;
     }
 
-    public function __toString()
+    public function __toString(): string
     {
         return $this->_name;
     }