diff --git a/TTS/GTTS.py b/TTS/GTTS.py
index c493d73..2e2d530 100644
--- a/TTS/GTTS.py
+++ b/TTS/GTTS.py
@@ -10,7 +10,7 @@ class GTTS:
         self.max_chars = 5000
         self.voices = []
 
-    def run(self, text, filepath, random_voice=False):
+    def run(self, text, filepath, random_voice: bool = False):
         tts = gTTS(
             text=text,
             lang=settings.config["reddit"]["thread"]["post_lang"] or "en",