Inspired by We had a unit test once which only failed on Sundays, write a program or function that does nothing but throw an error on Sunday, and exit gracefully on any other day.

###Rules:

• No using input or showing output through the usual IO methods, except to print to STDERR or your language's equivalent on Sunday.
• Your program may use a Sunday from any timezone, or the local timezone, as long as it is consistent.
• This is code-golf, so the shortest bytecount in each language wins!

I'll wait til Sunday to check the answers ;)