Update util_arg.py

Author: tsubramanian

utool/util_arg.py

@@ -1237,7 +1237,7 @@ def get_cmdline_varargs(argv=None):
 
 # Do I like these more?
 # varargs = get_varargs
-argval = get_argval
+argval_ = get_argval
 argflag = get_argflag