From a1c3ba8543e2351f0781614de402f5a0f868c38c Mon Sep 17 00:00:00 2001
From: Meritoo <github@meritoo.pl>
Date: Thu, 20 Jun 2019 20:21:14 +0200
Subject: [PATCH] Fix "Cannot call method sub on possibly null value" bug
 pointed by Psalm

---
 src/Utilities/Date.php | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/Utilities/Date.php b/src/Utilities/Date.php
index 6b614f6..4d950fa 100644
--- a/src/Utilities/Date.php
+++ b/src/Utilities/Date.php
@@ -125,7 +125,10 @@ class Date
 
                 if (null !== $nextMonth) {
                     $dateEnd = $nextMonth->getStartDate();
-                    $dateEnd->sub(new DateInterval('P1D'));
+
+                    if (null !== $dateEnd) {
+                        $dateEnd->sub(new DateInterval('P1D'));
+                    }
                 }
 
                 break;