diff --git a/src/PeriodTraits/PeriodOperations.php b/src/PeriodTraits/PeriodOperations.php
index a3ccd84..c9b08cc 100644
--- a/src/PeriodTraits/PeriodOperations.php
+++ b/src/PeriodTraits/PeriodOperations.php
@@ -40,7 +40,7 @@ public function overlap(Period ...$others): ?static
     {
         if (count($others) === 0) {
             return null;
-        } else if (count($others) > 1) {
+        } elseif (count($others) > 1) {
             return $this->overlapAll(...$others);
         } else {
             $other = $others[0];
@@ -119,7 +119,7 @@ public function subtract(Period ...$others): PeriodCollection
     {
         if (count($others) === 0) {
             return PeriodCollection::make($this);
-        } else if (count($others) > 1) {
+        } elseif (count($others) > 1) {
             return $this->subtractAll(...$others);
         } else {
             $other = $others[0];
diff --git a/tests/Operations/OverlapTest.php b/tests/Operations/OverlapTest.php
index 1eb3f91..f2421a5 100644
--- a/tests/Operations/OverlapTest.php
+++ b/tests/Operations/OverlapTest.php
@@ -186,7 +186,7 @@ public function passing_empty_period_collection_returns_null()
         $current = Period::make('2018-01-01', '2018-01-31');
         $emptyCollection = new PeriodCollection;
 
-        $diff = $current->overlap(... $emptyCollection);
+        $diff = $current->overlap(...$emptyCollection);
 
         $this->assertNull($diff);
     }
diff --git a/tests/Operations/SubtractTest.php b/tests/Operations/SubtractTest.php
index 616a2e3..550b9d6 100644
--- a/tests/Operations/SubtractTest.php
+++ b/tests/Operations/SubtractTest.php
@@ -231,7 +231,7 @@ public function passing_empty_period_collection_returns_same_period_within_colle
         $current = Period::make('2018-01-01', '2018-01-31');
         $emptyCollection = new PeriodCollection;
 
-        $diff = $current->subtract(... $emptyCollection);
+        $diff = $current->subtract(...$emptyCollection);
 
         $this->assertInstanceOf(PeriodCollection::class, $diff);
         $this->assertCount(1, $diff);