diff --git a/cpdctrl/led_script.py b/cpdctrl/led_script.py
index d38e9fe..ecb01df 100644
--- a/cpdctrl/led_script.py
+++ b/cpdctrl/led_script.py
@@ -76,6 +76,8 @@ class LedScript:
             self.script = LedScript.parse_script(script, ignore_errors=False)
             self.filepath = script
             self.auto_update = auto_update
+        else:
+            raise ValueError("Invalid value for script: Muse be int, np.ndarray or str")
         self.observer = None
         if self.auto_update:
            self.start_updating()