Bugfix in anti-email username check

src/rumchat_actor/__init__.py

@@ -149,7 +149,7 @@ def __init__(self, init_message = "Hello, Rumble!", ignore_users = ["TheRumbleBo
         self.password = kwargs.get("password")
 
         #Username must not be an email
-        if "@" in self.username:
+        if self.username and "@" in self.username:
             print("Username cannot be provided as email, must be displayed username.")
             self.username = None