diff --git a/yunohost.py b/yunohost.py
index 42e062a1..981e899a 100644
--- a/yunohost.py
+++ b/yunohost.py
@@ -137,6 +137,8 @@ def validate(pattern, array):
         Boolean | YunoHostError
 
     """
+    if array is None:
+        return True
     if isinstance(array, str):
         array = [array]
     for string in array: