I think you had an issues with [curly braces](http://docs.python.org/2/library/string.html#format-string-syntax).

>Format strings contain “replacement fields” surrounded by curly braces {}. Anything that is not contained in braces is considered literal text, which is copied unchanged to the output. If you need to include a brace character in the literal text, it can be escaped by doubling: {{ and }}.