allow tone frequency of zero

Author: RufusVS

adafruit_funhouse/peripherals.py

@@ -96,8 +96,8 @@ def play_tone(frequency, duration):
         It will attempt to play the sound up to 3 times in the case of
         an error.
         """
-        if frequency <= 0:
-            raise ValueError("The frequency has to be greater than 0.")
+        if frequency < 0:
+            raise ValueError("Negative frequencies are not allowed.")
         attempt = 0
         # Try up to 3 times to play the sound
         while attempt < 3: