Standard response to lack of arguments

unicode.py

@@ -7,11 +7,17 @@ class Unicode(BotPlugin):
     @botcmd
     def ord(self, message, args):
         """Runs ord() on the characters given"""
+        if not args:
+            return "**Usage**: !ord <characters>"
+
         return [ord(c) for c in args]
 
     @botcmd
     def chr(self, message, args):
         """Runs chr() on the numbers given"""
+        if not args:
+            return "**Usage**: !chr <numbers>"
+
         try:
             return ''.join([chr(int(i)) for i in args.split()])
         except ValueError as e: