Check falsiness instead

Author: godlygeek

Lib/cmd.py

@@ -273,7 +273,7 @@ def complete(self, text, state):
             endidx = readline.get_endidx() - stripped
             if begidx>0:
                 cmd, args, foo = self.parseline(line)
-                if cmd in ('', None):
+                if not cmd:
                     compfunc = self.completedefault
                 else:
                     try: