don't bother with ValueError message, since it reflects an internal coding mistake

Author: dhalbert

adafruit_sdcard.py

@@ -245,7 +245,7 @@ def _cmd(self, card, cmd, arg=0, crc=0, response_buf=None, data_block=True, wait
             # arg can be a 4-byte buf
             buf[1:5] = arg
         else:
-            raise ValueError("bad arg")
+            raise ValueError()
 
         if (crc == 0):
             buf[5] = calculate_crc(buf[:-1])