Refactor and rename some import things.

app/Support/Steam.php

@@ -270,6 +270,20 @@ class Steam
         return $list;
     }
 
+    /**
+     * @param string $amount
+     *
+     * @return string
+     */
+    public function negative(string $amount): string
+    {
+        if (bccomp($amount, '0') === 1) {
+            $amount = bcmul($amount, '-1');
+        }
+
+        return $amount;
+    }
+
     /**
      * @param $string
      *
@@ -305,8 +319,6 @@ class Steam
 
     }
 
-    // parse PHP size:
-
     /**
      * @param string $amount
      *