diff --git a/.travis.yml b/.travis.yml
index 9f59935..3d63462 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,5 @@
 os:
   - linux
-  - osx
 language: php
 php:
   - 7.0
diff --git a/src/Phpml/Classification/KNearestNeighbors.php b/src/Phpml/Classification/KNearestNeighbors.php
index 95ebeaf..594438b 100644
--- a/src/Phpml/Classification/KNearestNeighbors.php
+++ b/src/Phpml/Classification/KNearestNeighbors.php
@@ -67,7 +67,7 @@ class KNearestNeighbors implements Classifier
      *
      * @throws \Phpml\Exception\InvalidArgumentException
      */
-    private function kNeighborsDistances(array $sample): array
+    private function kNeighborsDistances(array $sample)
     {
         $distances = [];