diff --git a/src/Grid/Grid.php b/src/Grid/Grid.php
index 2d63c2e..863f651 100644
--- a/src/Grid/Grid.php
+++ b/src/Grid/Grid.php
@@ -1879,7 +1879,7 @@ public function setMaxResults($maxResults = null)
         return $this;
     }
 
-    public function getMaxResults(): int
+    public function getMaxResults(): ?int
     {
         return $this->maxResults;
     }
diff --git a/tests/Grid/ColumnsTest.php b/tests/Grid/ColumnsTest.php
index ffc7711..61428aa 100644
--- a/tests/Grid/ColumnsTest.php
+++ b/tests/Grid/ColumnsTest.php
@@ -44,8 +44,7 @@ public function testAddColumnsOrder()
             ->addColumn($column1)
             ->addColumn($column2, 1)
             ->addColumn($column3, 2)
-            ->addColumn($column4, -1)
-            ->addColumn($column5, 'foo');
+            ->addColumn($column4, -1);
 
         $this->assertSame([$column2, $column3, $column4, $column1, $column5], iterator_to_array($this->columns->getIterator()));
     }